Stretching across continents and civilizations, the 40th parallel north, a circle of latitude that is 40 degrees north of the Earth's equatorial plane, is more than just a line on a map — it is a zone of climatic balance, human civilization, and historical development.

From ancient trade routes to modern megacities, this latitude line has long shaped economies, cultures and the flow of ideas. A recently aired travel reality show, Wow the World, brought together a group of Chinese celebrities to visit historical cities along the iconic belt, such as Beijing, Rome and Madrid — blending travel, history and high-stakes knowledge challenges into a thrilling series.

The main cast includes actors Sun Honglei, Li Naiwen, Chen He, Liu Yuning, Gong Jun, and Chen Xingxu, alongside actresses Wang Yuwen and Ouyang Didi, who collaborate to complete a series of missions during their travels.

"This group shares a common curiosity about the world," explains Yan Zhihua, the show's executive producer.

Experts such as Shi Zhan, a professor at the Institute for the Global History of Civilizations, Shanghai International Studies University, were invited to provide cultural and historical context for each location visited by the cast.

The show also features several minigames that allow the cast to interact with locals and experience cultural exchange. For example, in one challenge, foreigners listen to Chinese songs through headphones and hum the melody, while the cast guesses the original lyrics based solely on the humming.

Beyond visiting historical attractions and sampling local cuisine, the team members immersed themselves in cultural experiences, such as participating in a castell (human tower) performance and meeting a talented Flamenco dancer in Spain. While the production unit carefully planned urban exploration routes, they also embraced serendipitous encounters along the way.

"In a small Italian town, we met an elderly man who seemed to know everyone. He recommended hidden gems and even took us to a cliff where local teens were jumping into the sea for fun," recalls Yan.

She notes how this filming experience differed from her previous rushed travels through these countries.

"When you have in-depth travel experience and engage with locals, you become more open-minded — better at understanding the differences between people," she says, hoping the reality show's viewers will observe the world through a similar lens.

"Algorithms keep feeding us content we already like, creating a so-called 'echo chamber'. I want our viewers to break out of that, to see the world with curiosity rather than stubbornness."

Recalling her most unforgettable moment, Yan describes a day in Catania, Italy, also the hometown of opera composer Vincenzo Bellini, in a bustling square.

"I was buying strawberries when a passerby began singing. Soon, the whole crowd joined in — like surround sound. Our cast sang a Cantonese song in response, and right after that, everyone was dancing hand-in-hand."

Then, a local elderly man grabbed their microphone and yelled, "I love China!"

"That moment — when music erased borders — gave me goose bumps all over," Yan says.