CHONGQING, China—An elevated train cuts through a residential high-rise. What looks like a street-level plaza is also the roof of a cliff-side building, 22-stories high. At night, the neon skyline lights up like a scene from “Blade Runner.”

This futuristic Chinese megacity built on mountains seems like science fiction—which is exactly why Florida retirees Bev and John Martin had to see it.

“It was just this feast for your eyes everywhere you turn,” said Bev, 62.

China has long awed visitors with wonders such as the Great Wall and the terracotta warriors buried in an ancient tomb. Now visitors are being dazzled by Chongqing’s vision of a real-world cyberpunk city.

Until a few years ago, Chongqing was largely a trivia answer: the world’s most populous city by some measures, with 32 million people in a South Carolina-size area. World War II history buffs knew it as the Chinese Nationalists’ wartime capital.

Then viral videos of its impossible architecture changed its image. Suddenly, many Chinese and international travelers alike felt they had to visit.

Chongqing welcomed 120 million tourists who stayed overnight last year, up 17% from 2023. In the first half of this year, Chongqing’s border checkpoints handled a record number of foreign nationals—but only 330,000, so overseas visitors who make it here can still brag about visiting a hidden gem.

There are few direct flights from Europe and the U.S., so many visitors transit through Beijing, Shanghai or another connection.

Many credit the tourism surge to social-media influencers, such as “Chinese Trump,” a Chongqing native named Ryan Chen who does a pitch-perfect impression of the U.S. president while eating the city’s signature spicy hot pot. Or local Jackson Lu, who shows a spiraling bus ride on a 20-story-tall elevated highway in a video with 56 million views across TikTok and Instagram.

Lu, a 28-year-old tour guide, said most of the skyscrapers were built in his lifetime. But the charm is that they are surrounded by towering, elevator-less 1980s apartment buildings, where people hang clothes to dry in metal window cages.

“There’s this clash between the old and the new,” he said. His dream was to make Chongqing the backdrop of a Tom Cruise action movie.

Many international visitors have to apply for tourist visas, including Felix Donaldson, a 29-year-old academic researcher from the U.K., who spent a recent evening in Chongqing on a nighttime river cruise.

China has become easier to navigate for non-Mandarin speakers such as Donaldson. Payment and translation apps have made things smoother. His only complaint: squat toilets.

The city may be in its Goldilocks period: convenient enough for foreigners, but not overrun with them yet. The hassle was worth it for Bev and John Martin, who documented their trip on YouTube showing sights such as a neon-lit food street and the Yangtze River aerial tram.

“Chongqing was the unknown but fabulous city that you need to visit,” Bev said.