Concept photo for Li Sibei and Cai Zeyu's "Paris Heartbeat" design proposal for the Notre-Dame Cathedral Photo: Courtesy of Cai Zeyu

Li Sibei

Cai Zeyu

Concept photo for Li Sibei and Cai Zeyu's "Paris Heartbeat" design proposal for the Notre-Dame Cathedral Photo: Courtesy of Cai Zeyu

On April 15 2019, over 800-year-old Notre-Dame Cathedral was engulfed by a fire. The spire of the cathedral collapsed during the fire and about two thirds of the roof was destroyed. 

French President Emmanuel Macron vowed to rebuild the cathedral after the inferno. 

Looking to get the general public interested in the endeavor, GoArchitect, an independent book publisher in the US, kicked off a free-entry design competition on May 9 dedicated to rebuilding Notre-Dame Cathedral. The winners would be chosen by an online vote.

Within two months, GoArchitect received more than 200 design proposals from 56 different countries and regions. 

Among these brilliant proposals, the work of two Chinese architects, Cai Zeyu and Li Sibei, stood out from the competition with more than 30,000 votes from public.

On Wednesday, GoArchitect revealed on its official website that Cai and Li were the official winners of the competition and that they would get $1,000 as a prize. 

Power of unity

The loss of the cathedral was a huge blow to architecture lovers everywhere.

In the two days following the devastating blaze, nearly $1 billion was pledged by donors from across the world, including some major companies.

What's more, the rebuilding of the Notre-Dame Cathedral captured the attention of architects from all over the world. 

The Eight Inc., the design company who designed the first apple store, suggested that the reconstruction could use modern materials. 

The studio suggested that structural glass could be used to rebuild the spire and roof. In their concept photos the cathedral appears very shiny under the lights of Paris at night.

In the opinion of French designer Mathieu Lehanneur, people should remember the fire forever, so his design for the cathedral involves a 100-meter-high golden column of "fire" made from gold foil and carbon fiber. 

Heart of the city

Cai and Li's design is called "Paris Heartbeat." The keystone of the design is what they call the "City Kaleidoscope," which also involves a "Time Capsule."

The two want to replace the old spire with a new one that is made up of a kaleidoscope of multifaceted mirrors that, combined with a mirror roof, constantly reflect an ever changing urban environment. 

Floating at the top of the spire using magnetic levitation technology is the "Time Capsule," which is meant to open every half century. The "Time Capsule" moves rhythmically up and down, breathing and beating together with the city.

For the two, the "Time Capsule" is the most exciting part of the design.

"The 'Time Capsule' rhythmically rises and falls, I believe that it can be achieve with present technology," Cai explained. 

"We want people to feel the 'heartbeat' and it has a scientific basis."

The inside reflection of the tower spire creates a "City Kaleidoscope." The vibrant glass changes the color of the light while the structure itself casts a shadow. Cai told the Global Times that the kaleidoscope is inspired by the cathedral's colorful Rose Window, which survived the inferno.

Cai and Li said in their design fits with the idea that Notre-Dame has witnessed Paris' history over the past 800 years and that even this disaster can become a part of that history.

The reflection from the "City Kaleidoscope," people can remind people of this history and inspire them to look forward to the future of the cathedral.

"It burns, it survives, and it breathes with the ever-changing world," said Cai and Li.

Talented architects

Cai is from Hangzhou, Zhejiang Province and started his architecture career after graduating from Tsinghua University. Li is from Beijing and studied at the Beijing University of Technology. 

Both of them got their master's degree from Cornell University and are now working at the SOM architecture firm in Chicago, US.

"We are very excited, including our families and friends, to have Chinese architects be recognized on an international stage," Cai told the Global Times.

Both Cai and Li have visited the cathedral, although it was at different times. 

"The scene of the spire falling in the fire shocked both of us," said Li. 

"After that, we kept following the situation of the cathedral and we quickly started to work on it after GoArchitect launched the competition."

Cai and Li devoted themselves to their design and used their leisure time to study the historical building. 

"We studied the Notre-Dame Cathedral's structure, including the color of the Rose Window, the geometric forms of the spire, which changes into 10 hexagons from an octagon, and its shape and scale," said Cai. 

"Our design looks quite modern, but we actually made an effort to follow the historical information that we found and try to interpret them through architecture."

The more they learned, the more their plans evolved over time.

"As our research continued, we gradually found out that the Notre-Dame Cathedral is a living thing," said Li. 

"We believe that our design process was a process of listening, watching and feeling." 


Newspaper headline: Reflecting history