Why The Name?

Because it's a glen, in the Scottish sense of a deep valley, and it's great: more than 70 miles of geological fault running south-west from Inverness on the Moray Firth to Fort William on the Atlantic Ocean, offering the visitor spectacular landscapes, historical sites and vast expanses of water - notably Loch Ness.

A glance at the map of Scotland shows an awesomely obvious rift, as though the northwestern quadrant of the country had sheared off, grinding past Fort William and Inverness in the general direction of Norway. This is broadly what created the Great Glen, which forms the boundary between the Grampians and the West Highlands.

The area provides numerous possibilities for leisurely picnics in fine scenery, or vigorous outdoor activities; indeed, the southern end of the Great Glen is about to host the 2007 Adventure Racing World Championship, from 24 May until 2 June - see www.arwc2007.com.

Can I Walk It?

Yes. The Great Glen has been a vital communication link for centuries, but in 2002 the Great Glen Way, a properly signposted coast-to-coast trail, was opened. It includes canal towpath, forest tracks and a few sections of public road. The 80-odd miles of the route can be walked in five to six days, but it is also ideal for shorter outings. The prevailing wind is south-westerly, so it makes sense to start in Fort William and head north.

The Great Glen Way ( www.greatglenway.com) is a partnership between the Forestry Commission, British Waterways, Scottish Natural Heritage and the Highland Council. Detailed maps are available from the website, and its ranger service coordinates maintenance work and activity days for children.

What About Cycling?

The Great Glen Cycle Route runs for 80 miles along the northern shore of the Caledonian Canal and lochs. Most of its 12 sections follow the canal, B-roads or designated cycling tracks, and are of varying levels of difficulty, from flat towpaths to challenging overland trails.

The majority of the path is part of the National Cycle Network ( www.sustrans.org.uk for details of the path). It is well signposted, with information on accommodation, catering, etc, available on panels.

Other cycle-paths also exist, notably from Fort Augustus to Inverness via the southern shore, and around Leanachan Forest, where specialised mountain-biking trails have been developed by the Aonach Mor Ski Centre ( www.nevisrange.co.uk/summer). Bikes can be hired at several locations - if you rent one from Off Beat Bikes in Fort William ( www.offbeatbikes.co.uk), the company will let you drop it off in Inverness; the cost including rental and drop-fee is a total of £48 for two days.

Must I Stick To The Low Road?

The A82, which runs all the way along the Great Glen linking Fort William and Inverness, is an exceptionally busy road, especially in summer. In contrast, the road on the southern shore of Loch Ness (now the B862/B852) is much quieter. It has a grim history, being built by General Wade in the 18th century with the aim of repressing the Highlanders. Today, it provides a beautiful perspective of the loch, with excellent photograph and picnic opportunities. There is even Loch Ness's only beach, at Dores, if you're feeling hardy.

Along the way, the road passes Thomas Telford-designed piers in Inverfarigaig and Foyers, an intact General Wade bridge at Whitebridge and the Suidhe Chuimein viewpoint giving superb prospects along the Stratherrick valley.

History fans will find the remains of an Iron Age fort at Dun Deardail and the clan graves at Dunlichity (where Jacobite soldiers prepared their weapons before Culloden). Forest tracks on either side of the Glen provide peaceful and unpolluted alternatives to both roads.

Any Interesting Wildlife?

A little patience and, ideally, a pair of binoculars are all that is required. Anyone heading away from the villages and main roads is likely to spot red or roe deer, otters, red squirrels and mountain hares. Nor should you have to wait too long before seeing herons, ducks, pheasants, eagles and more.

The great strength of the Great Glen is the diversity of terrain (lowland fen, swampland, gorge woodland) which provides refuge for rare birds, butterflies, plants, trees and insects. The region has several sites of special scientific interest: South Laggan Fen, Urquhart Bay Wood, Easter Ness Forest, Glen Tariff and Inverfarigaig. To the north, the RSPB sanctuary at Loch Ruthven and the SSSI at Inverarnie provide further opportunities for observing wildlife.

A large school of bottlenose dolphins has taken up residence in the Moray Firth, and boat trips take visitors very close. The best operators (such as Moray Firth Cruises, www.inverness-dolphin-cruises.co.uk) are those who follow a code of conduct aimed at minimising stress to these remarkable mammals.

And The Biggest Beast Of All?

As far back as AD565, St Columba was reporting that some of his monks had been attacked by a mysterious "water horse", but the Loch Ness Monster's current incarnation dates back only to the 1930s, when the A82 was completed. In 1934 a photograph was published showing a head and long neck emerging from the dark waters, and the modern myth was born. It prevails, even though the photo was later acknowledged to have been a fake. The loch's size (23 miles in length) and uneven depths (some areas are over 750 feet deep) allow for continuing speculation.

With two competing Monster exhibitions, Drumnadrochit is the centre of the Nessie industry and a shrine to the power of hype. The Original Loch Ness Monster Visitor Centre ( www.lochness-centre.com) has the obligatory video, jumbo-sized monster models and shelves of souvenirs, while the Loch Ness 2000 Exhibition ( www.lochness.com) focuses more on eye-witness stories and research.

Are There Less Tacky Tourist Attractions?

Plenty. Just beside Drumnadrochit, Castle Urquhart ( www.historic-scotland.gov.uk) has towered over the loch for centuries. Its strategic * * location meant that it changed hands several times, finally being blown up in 1692 to prevent it falling into Jacobite hands. A visitors' centre is now located behind the picturesque ruins, open 9.30am-5.30pm daily, £6.50.

On the opposite shore, the 140-feet Falls of Foyers (in Gaelic Eas na Smuid, the "Waterfall of Smoke") have been drawing visitors for over a century. In 1896 this was the site of Britain's first hydroelectric power station. The falls are best approached on the trail from Upper Foyers.

The village of Fort Augustus is further evidence of the Great Glen's strategic importance in controlling the Highlands. It developed when barracks were built here after the first Jacobite Rebellion in 1715. The building was subsequently taken over by Benedictine monks, but their abbey has now been converted into flats. More history is on display at the Caledonian Canal Heritage Centre, in a converted lock-keeper's cottage beside a series of five locks, and at the Clansman Centre, which celebrates the Highland traditions that were largely destroyed after the battle of Culloden.

Moving south to Loch Oich, the ruins of Invergarry Castle are another monument to the Forty-Five Rebellion that ended at Culloden: it was destroyed in 1746 after MacDonnel of Glengarry assisted Bonnie Prince Charlie.

I Want To Take To The Water

From the Moray Firth to Loch Linnhe, via Loch Ness and the lesser-known Lochs Oich and Lochy, all linked by the Caledonian Canal, there are multiple options for messing about on the water. The easiest way is to hop on one of the many boat-trips, available all along the glen. Options include: from Inverness, Jacobite Cruises ( www.jacobite.co.uk); from Drumnadrochit, the Nessie Hunter (run by the Original Loch Ness Visitor Centre) or Deep Scan Cruises (run by the Loch Ness 2000 Exhibition); from Fort Augustus, the Royal Scot ( www.cruiselochness.com); and from Fort William, Crannog Cruises (01397 700714; www.crannog.net).

Alternatively, you could try your hand at the helm: Inverness-based Caley Cruisers ( www.caleycruisers.com) have a 40-strong fleet of easily operated motor cruisers for short-term rental. The Great Glen Water Park at Loch Oich ( www.monsteractivities.com) offerswhite-water rafting, sailing, canoeing and a range of other activities. Tourist offices have information on fly fishing possibilities (and permits) throughout the area.

For something very different, take a week-long cruise on the converted Dutch barge Fingal of Caledonia.

Any City Life?

City status may only have been conferred on Inverness to mark the millennium, but is has long been the undisputed shopping and transport capital of the Highlands. Currently the UK's fastest-growing urban area, the metropolis has plans for further expansion - with the corresponding infrastructure, leisure facilities and nightlife to match.

The city centre itself is compact: the main sites of interest are the 19th-century castle (most of which is now the Sheriff Court, although there is a visitor attraction highlighting a Hanoverian garrison) and the Museum and Art Gallery (Castle Wynd). A short stroll from the castle, the Ness Islands make a pleasant picnic area, while the trail up Craig Phadraig is a robust afternoon walk. Culloden battlefield lies six miles to the east.

At the other end of the glen, Fort William is much smaller and has less immediate attractions - but is the gateway to Ben Nevis, Glencoe and the West Highland Way. The fort from which it took its name was destroyed in the 19th century, but the modern town along the shores of Loch Linnhe is a tourist magnet. This is also the starting point for the 42-mile train journey to Mallaig: the Jacobite Steam train sinews round the Glenfinnan viaduct as it heads for the coast ( www.westcoastrailway.co.uk), though you can cover the ground much more cheaply on a ScotRail service.

Will It Rain? Or Worse?

Inverness is nearer to the North Pole than either Moscow or Juneau, the state capital of Alaska, but, happily has a milder climate. However, unpredictability is the key word when it comes to Scottish weather, so come prepared, as strong winds can build up quickly on the lochs. Walkers in particular should ensure they have proper footwear and warm clothing, whatever the season.

Where Should I Stay?

There's no shortage of accommodation in the region, but summer reservations should be made as far in advance as possible. Visit Scotland ( www.visitscotland.com) provides comprehensive listings for B&Bs, self-catering facilities and hotels. Among the options, the Glengarry Castle Hotel, Invergarry (01809 501 254) boasts the ruins of Invergarry castle in its grounds, while the views along Loch Lochy from the Corriegour Lodge Hotel, Spean Bridge (01397 712 685) are magnificent. In Inverness, the Loch Ness House Hotel, next to the swing-bridge over the Caledonian Canal, is ideally placed for walkers and cyclists.

The Scottish Youth Hostel Association (reservations www.syha.org.uk) has a hostel at each end of the glen: the Loch Ness Youth Hostel, Glenmoriston and the Loch Lochy Youth Hostel, Spean Bridge. Several independent hostels also exist, including Morag's Lodge in Fort Augustus ( www.moragslodge.com, £15 to £48 per night).

How Do I Get There?

Rail is the best way to approach, because that way you get a taste of the Highlands before you reach the Great Glen. Both Fort William and Inverness are served from Glasgow Queen Street and London Euston; Inverness also has links from Edinburgh. Details from www.firstscotrail.com. Unfortunately, there are no direct rail links between Inverness and Fort William, although Scottish Citylink ( www.citylink.co.uk) has a two-hour bus service on the route.

Inverness is the air hub, with links from many UK airports, including Gatwick (easyJet and Flybe) and Heathrow (BMI). Inverness airport is eight miles east of the city, in Dalcross: its website has information on flight possibilities (www.hial.co.uk ; 01667 464 000).

Where Can I Find Out More?

Inverness Tourist Office: Castle Wynd, 01463 234 353, and the Fort William Tourist Office: Cameron Square, 01397 703781. Visit Scotland ( www.visitscotland.com) and Visit Highlands ( www.visithighlands.com) are excellent sources of information. Highland 2007 (www.highland2007.com ) has information on cultural events throughout the region.

The Forestry Commission has a range of leaflets on mountain biking, forest trails and other aspects of the glen, available from tourist offices or from www.forestry.gov.uk. The www.greatglendirect.com website is also useful.

Glen Nevis

A few miles south of Fort William, the 11-mile Glen Nevis provides a dramatic example of a glaciated valley and is a walkers' paradise. A location for Braveheart and Rob Roy, it is also the starting point for tackling Ben Nevis, Britain's highest mountain, at 4,406 ft (1344m), which is no easy stroll: conditions are very changeable, and climbers should be properly equipped. Starting from Achintee Farm, allow four to five hours to reach the (frequently misty) summit, and another two to three to descend. Fortunately, there are plenty of more accessible walks: three to four hours will take you to Dun Dearduil, an old hill fort; at the eastern end of the glen, and reached through a narrow gorge, the 330ft Steall Waterfall is the highlight of a wide, U-shaped valley.

On rainy days, retreat to the Glen Nevis Visitor Centre for displays on the area's wildlife and history (guided walks are also available). A few miles north of Fort William, the views from the Nevis Range Mountain Experience's mountain gondola are stunning ( www.nevisrange.co.uk).

Barge About

Every Saturday throughout the summer (which the crew optimistically defines as lasting from April until October), the Fingal of Caledonia climbs the flight of locks at each end of the Caledonian Canal. She's a lanky, well-heeled lass, her 125 feet having been turned into comfortable cabins for a dozen guests and slightly-less-comfortable cabins for half-a-dozen crew . The paying guests and the paid hands meet in the middle, at a generously provisioned galley.

That there are unlimited quantities of hearty food is crucial, because you are not here to enjoy yourself by lounging around on deck. The crew will see to that: they are young, gifted and back for another season of showing holidaymakers how to make the most of Scotland's great divide.

While Fingal sails slowly along Thomas Telford's maritime masterpiece, passengers are encouraged to cover the startling terrain in a variety of ways. Hidden in the gunwales is enough equipment to launch a multi-activity centre, which is what the vessel turns out to be. You can hike, mountain bike, windsurf or kayak the length of the Great Glen - and you have to unpack only once.

Fingal of Caledonia: www.fingal-cruising.co.uk.