Tate Modern is the second most visited venue in the country with 4.9m visitors, according to new research.
The Tate Modern saw a 21% rise in visitors in 2006
The site, in London's South Bank, saw an increase of 21% in the number of its visitors compared to 2005.
Blackpool Pleasure Beach topped the poll with 5.7m visits, although numbers were down 4%, said the Association of Leading Visitor Attractions (ALVA).
ALVA director Robin Broke said visitor numbers fell dramatically following the 7 July 2005 bombings.
Most London attractions saw visitor figures increase significantly in 2006, according to the ALVA's latest figures.
The British Museum, National Gallery, Natural History Museum and Science Museum were among the nation's favourite attractions.
Among the least visited attractions were the National Museum of Costume in Scotland and the National Wool Museum in Wales.
Mr Broke said the tourism industry was vibrant despite security alerts, punctual transport woes and a weak US dollar.
But he said Britain's attractions industry still needed financial support to help promote it "if this country is to compete globally".
"The figures show a marked increase for several attractions compared to their 2005 performance.
"This is partly explained by the affect of the July bombings of that year."