It was one of Ireland's tallest lighthouses, and for more than 100 years it has stood at the entrance to Belfast Lough, guiding ships safely to shore.
Now there are ambitious plans to save Mew Island Lighthouse's old optic - which could well be the biggest ever built - and install it in Belfast's Titanic Quarter, where it would form the focus of a new lantern room telling the story of lighthouses.
The optic is the lens that gathers the light and beams it from the lighthouse.
Titanic Foundation and Commissioner of Irish Lights are celebrating after winning a first-round pass from the Heritage Lottery Fund for their plan to restore the extremely rare hyper radial Fresnel lens that once formed the heart of the lighthouse on the outermost of the Copeland Islands.
With support from Ulster Garden Villages, the project can now progress to the second stage of the HLF application process.
If successful, the optic will be restored and housed in a new interpretive structure, made to resemble a lighthouse lantern room, close to the Titanic slipway.
The exhibit will be free, telling the story of lighthouses, their technological development, their light keepers, and their role in the proud maritime and industrial heritage of Belfast and Ulster.
The Mew Island optic, which was replaced by a modern solar-powered flashing LED in March 2015, has been transferred from Mew Island to the Irish Lights' offices in Dun Laoghaire, where experts are carrying out initial restoration work.
Mew Island lighthouse is one of the tallest in Ireland and was built when Belfast was the world centre of linen, shipbuilding and rope-making, and one of the world's most important ports.
The optic was made in Paris in 1887, and is possibly the largest ever built at a staggering 7 metres high and 2.6 metres wide, and weighing up to 10 tonnes.
It is one of only 18 still in existence, and is one of only three similar optics in Ireland, none of which are operational.
Over its lifetime, the optic was variously lit with town-gas, derived manually on the island from coal, vaporised paraffin and electricity.
The lighthouse replaced one that had been built on the Copelands in the 1700s but was in the wrong place, with the light blocked by land. Mew Island claimed many lives in the 180 years before the new lighthouse was built, including the slave ship Enterprise, which was on its way to Liverpool in 1803 with slaves and silver dollars when it was wrecked with all souls lost.
Kerrie Sweeney, chief executive of Titanic Foundation, said: 'This remarkable object is an amazing piece of industrial and scientific heritage and our proposal has really captured the public's interest.
"We are delighted to have secured support from Heritage Lottery and Ulster Garden Villages - this is a once in a lifetime opportunity to save and restore an artefact of national and international significance and create a legacy Belfast landmark which will inspire future generations."