Two attractions in Bristol's city centre are to close, making 45 people redundant, as At-Bristol has announced plans to focus on a science centre.
The centres are ear-marked for closure in April
A spokesperson for the charity-run centre said Wildwalk and the IMAX Theatre were less popular with the public and were expensive to operate.
The science centre will concentrate on providing interactive exhibitions in Explore and the Planetarium instead.
The charity blamed a lack of funding for the decision.
Dr Goéry Delacôte, chief executive of At-Bristol, said short-term funding and grants which the centre received when it opened in 2000 have now "come to an end or are significantly reduced in size".
"In addition, without the likelihood of long-term government funding becoming available for science centres in England, it is important that we move to make At-Bristol financially sustainable," he said.
Chairman Peter McIlwraith said: "I have consistently referred to At-Bristol's need for some form of long term financial support to sustain its current level of activity.
"With no realistic prospect of securing this, changes must now be made to secure At-Bristol's long-term future. The Board fully supports the proposed changes. I am optimistic about the future."
Ian Knight, West of England's head of operations for the South West Regional Development Agency, said it was working with Bristol City Council and other partners to try to find new uses for the Wildwalk and IMAX building.
"We have great sympathy for the staff at At-Bristol who are facing an uncertain future but we do understand the management's need to focus on establishing the long-term viability of the popular Explore Science Centre," he said.
The centres are ear-marked for closure in April.