Given that China seems to have over-invested in glass glass bridges over the past year or so, it’s pretty important that they establish that the bridges are, you know, safe to walk on.

And so, a brilliant plan was devised: Invite tourists onto a bridge and have them smash it with a sledgehammer.

On Saturday, roughly 30 visitors were brought onto the bridge at the Zhangjiajie Grand Canyon in Hunan province, given 5.5-kilogram (roughly 12-pound) sledgehammers and told to have at it, Xinhua reports. Supposedly both the longest (1,411 feet) and the highest (984 feet above ground) glass bridge on the planet, the Zhangjiajie bridge completed construction recently in spring 2016 and is apparently able to withstand the weight of 800 people at once. Originally slated to debut to the public in May, rainfall has pushed its opening date back to July, according to the South China Morning Post.

Thankfully, none of the sledgehammer-ers managed to collapse the bridge before it even opened, but many of them did leave cracks in the top layer of the glass. (The bridge has three layers of glass, and each layer is 0.6 inches thick.) To further prove the point, after 20 tourists left their marks on the bridge, a Volvo SUV weighing two metric tons (4,409 pounds) and containing 11 passengers drove over the cracked panels. Then, the final 10 took their turns.

“Even if the glass cracks, it will not break into pieces,” said Chen Zhidong, an official at the park. “Pedestrians can still walk on it.”

Publicity events like these have been staged to assuage potential visitors after cracks were discovered in a different Chinese glass bridge last year, causing a small panic. In that incident, which occurred at the bridge that had just opened at Yuntai Mountain in October 2015, a stainless steel cup managed to crack the glass, sending some running and screaming to the sides of the bridge. Although authorities did their best to assure visitors that the bridge was still safe to walk on, many remained skeptical, especially given that an entire pane had shattered, according to visitor Li Donghai, who posted about his experience on the blog site Weibo.

Earlier this month, BBC Click reporter Dan Simmons was given a similar chance to test the safety of the bridge — although he was merely allowed to smash a separate panel, not the actual bridge. His first strike shattered the top layer, but even after more than a dozen blows, the bottom two layers were undamaged.

In a separate test conducted by bridge officials, 25 people jumped on one panel. All three layers of glass cracked, but they still didn’t break through the bridge.