On April 15, 2019, fire has set the Notre Dame Cathedral a blaze, damaging the roof, spire, and some works of art. The world mourned and efforts have since been made in reviving the beloved landmark. French legislators have announced that there would be an international design competition in light of the damaged cathedral.

Since then, several architects have come forward with different proposed designs that could yet again crown the landmark.

A French architectural, firm Vincent Callebaut has come forward with their eco-friendly proposal for the cathedral's reconstruction, which the firm dubbed as the "Palingenesis roofing design."

The firm's design features a massive stained glass spire which is actually a greenhouse system that generates clean energy for the cathedral, the design is aptly named. In Greek, "palingenesis" means "Rebirth".

The architectural firm stated that through energetic solidarity with the body of the historic monument, the three-dimensional contemporary Gothic stained glass graft would produce all the electricity, passive ventilation, and heat that the whole cathedral needs. Vincent Callebaut explained that this can be done by combining advanced renewable energies and passive systems.

The three-dimensional crystal glass will be subdivided into faceted diamond shape elements which sits on a new set of wooden frames. Light is absorbed and transformed into power by the crystal glass which consists of an organic active layer made of hydrogen, carbon, oxygen, and nitrogen. The firm explained that the energy stored in the hydrogen fuel cells would be direct with distributed throughout the whole cathedral.

The greenhouse effect is avoided as the crystalline scales open at the bottom of the frame along the acroterion of the transept in the nave. This would mimic a wind-powered chimney, creating a natural air flow towards the top of the spire.

The new roof design could also support of new fruit and produce garden. Management of the said garden, which could produce up to 21 tons of fruit and vegetables every year, could, of course, be done by charity workers or by cathedral staffers. This is one opportunity for the Notre Dame to hold a weekly farmers market on its forecourt.

Other designs submitted for the new spire of the cathedral has taken an eco-friendly approach as well.
Summum Architecture is conceptualizing a roof that could be a sanctuary for endangered birds and insects. Studio Nab is looking to build a greenhouse that houses beehives, serving as a pollinator sanctuary and at the same time and educational center to the public. Studio Drift is looking to use recycled ocean plastic in building the new spire and rooftop of the landmark.