Banksy's Dismaland theme park has raked in a whopping £20 million for Weston-super-Mare's economy.
Visit Somerset said that John Turner, the county's Destination Management Organisation chief executive, initially predicted a £7 million boost.
Mr Turner said: "This has been a global phenomenon of major importance for the region, as we have seen a large international surge in what is a predominately a solid and reliable domestic market.
See also: Banksy's Dismaland in pictures
"The majority of businesses have been reporting up to 50% increases on last year and as this event overlapped in the most crucial time in the holiday calendar, could well see a further £20,000,000 coming back into the local and regional economy."
Dismaland closes today (Sunday 27 September) after a five-week run.
See also: Robot hotel opens at Japanese theme park
According to the Daily Mail, the satirical theme park has welcomed more than 150,000 visitors.
Visitors enter the theme park, which features work by dozens of artists, through a security check made from cardboard by Bill Barminski.
They are greeted with a view of the park and Banksy's fire-ravaged fairytale Cinderella Castle showing "how it feels to be a real princess".
There are boats full of asylum seekers which can be driven round a pond, two juggernauts performing ballet and a camp training guests how to break into bus billboards.
Banksy's Dismaland trailer is a brilliant Disneyland parody (see the video)
World's weirdest amusement parks