A Grade I listed Georgian building in Buckinghamshire - bought and transformed into a centre for science at a cost of £10m - has opened.
The Royal Society and the Kavli Foundation spent £10m on the purchase and refurbishment of Chicheley Hall near Milton Keynes.
The Kavli Royal Society International Centre is hosting events and will be officially opened later this year.
A new residential facility there can accommodate up to 100 scientists.
Martin Rees, president of the Royal Society, has said he hopes the facility will become a world renowned centre for British science.
"Science is at the heart of some of the biggest global challenges that are facing us - disease, food shortages, water shortages, climate change," he said on The Royal Society's website.
"We will only rise to meet these challenges by getting together the best minds."
The Kavli Royal Society International Centre forms part of the Royal Society's 350th anniversary celebrations.