Glass is the new wood.

Architects around the world have started sharing their visions of how Notre Dame should be rebuilt following a fire that destroyed the cathedral’s roof, and a lot of them are favoring 21st-century looks over 18th-century traditions.

French Prime Minister Édouard Philippe has launched an international competition to replace the iconic spire that collapsed in the inferno. “This is obviously a huge challenge, a historic responsibility,” Philippe said last month, calling for the new design to be “adapted to technologies and challenges of our times.”

“The ideal outcome would be a respectful combination of the dominant old with the best of the new,” said British architect Norman Foster, whose projects include a modernization of the German Reichstag, in an emailed statement. And while Foster has not submitted a proposal and said he has no plans to do so, others seem to agree with his vision.

Most submissions made public by their creators on social media call for the wooden beams, which gave the cathedral’s attic its nickname “the forest,” to be replaced with steel and glass. Some even propose for the roof to become a public space with panoramic views of Paris.

A decision on a new Notre Dame is months away, as experts are still assessing the damage. But once a design is announced for the cathedral, architects, construction workers and master craftsmen will have to race to meet the five-year deadline imposed by French President Emmanuel Macron.

Foster is optimistic: “France has an enviable reputation for the realization of Grand Projects. Given this background, there is no reason why President Macron’s optimistic commitment cannot be achieved.”