Italy's government is seeking bids from engineers to rebuild the floor of the Colosseum in Rome and return it to its former glory.
The project will have a total budget of 18.5m euros (£16.7m; $22.5m), and the work is due to start next year.
The retractable floor is expected to feature trap doors and hidden lifts.
"The reconstruction... is a great idea which has gone around the world," Culture Minister Dario Franceschini said in a statement.
"It will be a major technological intervention that will offer visitors the opportunity to, not only see the underground rooms... but also appreciate the beauty of the Colosseum while standing in the centre of the arena," he added.
The culture ministry said the redesigned floor, and any trap doors or mechanical components, must be able to close quickly in order to protect the underground spaces from rain.
A new floor would "allow the public to fully understand the use and function of this icon of the ancient world", the statement added.
The ministry said cultural events, such as concerts and theatres, could potentially be held in the Colosseum once the floor is installed.
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Built 2,000 years ago, the Colosseum was the biggest amphitheatre built in the Roman Empire, and hosted gladiatorial fights and other public entertainments.
It remains one of Italy's most famous landmarks, and about 7.6 million people visited the site in 2019.
Proposals to rebuild the Colosseum's floor must be submitted by 1 February, and the project is expected to be completed by 2023.