Trustees of the troubled Earth Centre environment park have said it is "no longer viable" and announced 51 of its 75 staff were being made redundant.
School parties are still being admitted to the site
The £50m centre in Conisbrough, near Doncaster, South Yorkshire, closed its doors to day visitors on Monday as the board of trustees held emergency talks.
They are to hand the park to Doncaster Council in a bid to keep it open.
The mayor of Doncaster, Martin Winter, said: "We will be exploring ways in which that can be done."
The park was hailed by the government as even "greater" than the Millennium Dome when it opened in 1999 with more than £36 million in funding from the Millennium Commission.
Today, Mr Winter took steps to assure people that the centre would not be a drain on the public purse.
"I can give the assurance that we will not be taking over the centre with any financial risks to the taxpayers of Doncaster and will announce further details of our plans in the coming weeks," he said.
Central to the Earth Centre's problems was the failure to attract the expected number of visitors.
Built on the site of a former colliery, it aimed to show people how to live and work in a sustainable environment.
It was expected to attract 500,000 visitors in its first year but only 80,000 came through the gates.
As a result some staff were made redundant and the project was closed for a time in June 2000 before reopening on a smaller scale.
Only pre-booked parties are currently being admitted to the site.