Belfast's Waterfront Hall has reopened after a major overhaul.
The £29.5m investment is expected to bring in £100m for the local economy in the next five years.
The city centre landmark has doubled in size to create an international venue capable of attracting major conferences for up to 5,000 delegates a day.
Thirty international and national conferences have already been secured for the next three years - among them the BBC Good Food Show, the World Council of Credit Unions and the Royal College of Nursing.
Belfast Lord Mayor Arder Carson said: "The new-look Belfast Waterfront in 2016 will elevate our city's global profile, bringing growth, prosperity and opportunities to Belfast and its people.
"It is a cornerstone of our vision for city centre regeneration and will add to our reputation as a vibrant global brand."
He expected conference delegates would spend 50,000 days in the area each year by 2020 because of the new facilities, and two-thirds of those are expected to be from outside Northern Ireland.
From 2020, it is thought the expanded facility will bring in £45m a year for the local economy. The £29.5m investment was made by Belfast City Council, Tourism Northern Ireland and the European Regional Development Fund, through the European Sustainable Competitiveness Programme for Northern Ireland.