Instead of open roads, runners in southwestern China's Chongqing Municipality recently pounded the stairs in a "vertical marathon," ascending through 141 meters of elevation deep inside a mountain at the Hongyancun metro station, the deepest of its kind in China.

In October, Hongyancun station received international acclaim for its unique design and construction challenges, earning the gold medal for Project of the Year title at the International Tunneling and Underground Space Association awards.

To allow more residents and visitors to experience this engineering marvel up close, Chongqing organized the "vertical marathon" inside the station. Participants ascended the stairs, challenging the elevation gain, and received a personalized marathon plog souvenir at the finish line.

"To let everyone appreciate the architectural beauty of this station up close, we enhanced the supporting facilities and held vertical marathon events here," said Zou Guangjiong, deputy general manager and chief engineer of the rail transit design institute under Chongqing Transportation Development and Investment Group Co., Ltd. "We welcome people from around the world to come and experience its charm."

As upbeat music echoed through the station halls, groups of college students joined the race, cheering each other on as they climbed the long stairways.

"Experiencing the vertical marathon inside the metro station is very innovative and has boosted my motivation and energy," said Wen Yuchen, a student from Chongqing Medical and Pharmaceutical College.

Conquering the "vertical marathon" was no easy feat. The course extends about 340 meters in length, rises 116 meters vertically, and maintains a slope between 27 and 30 degrees with 860 steps, making it one of the most technically demanding metro stations in the world.

Under normal circumstances, passengers need to ride eight different escalators to reach ground level, a process that takes about 15 minutes. Just exiting this deep subway station is exhausting enough, let alone constructing it.

"Building China's deepest subway station inside the mountain was a huge challenge, but we did it for the people. This award honors the resilience of Chongqing," Zou said.

"The greatest challenge was not just the depth, but how to make it convenient for the public," said Zhou Jie, a senior engineer at the Chongqing rail transit design institute. "By optimizing the structure to follow the mountain's contours, we created a station that shortens travel distances and brings mountain and river communities closer together."

Built into the steep hillside, Hongyancun station opened a direct vertical passage linking the mountaintop neighborhoods with Jialing River Road below. Previously, residents had to take winding routes down the slope, a trip that took about 30 minutes. Now, with the vertical elevators inside the station, they can reach the riverside in just about five minutes, greatly improving travel convenience.

"Since Hongyancun station opened, going up and down the hill has become much easier. The subway has really shortened the distance in our daily life," said Wang Zhiqiang, a local resident.

Hongyan, the station's name, symbolizes the spirit of faith, unity and courage in Chinese culture. Inside, a "Chongqing Urban Spirit" exhibition invites visitors to learn more about the city's unique character and open attitude.

Integrating engineering innovation with cultural expression, Hongyancun station serves not only as a transport hub but also a vivid symbol of Chongqing's vitality and confidence on the global stage.