A vast bio-dome complex four times the size of Cornwall's Eden Project could be built in Bedfordshire.
The institute would be four times the size of the Eden Project
Stewartby's old brick pits have been shortlisted as one of three sites for the world's largest aquarium.
The rivals in the running for the massive £220m National Institute for Aquatic Life are Monmouthshire in South Wales and Liverpool.
The futuristic plans unveiled in London on Wednesday are by the team behind the Eden Project.
Philip Graf, of the National Institute for Research into Aquatic Habitats (Nirah), said the project would be full of live displays of animals in their habitats such as fish, reptiles, snakes and amphibians.
Stewartby pits is one of three short-listed sites for the project
Bedfordshire County Council spokesman Tim Malynn, who was at the launch, said it was a marvellous opportunity for the county and the wider area.
"This is going to be an absolutely fantastic catalyst for the future of Bedfordshire," he said.