A few incredibly brave climbers scaled up the world’s highest man-made climbing wall that runs up the face of a 540-foot-tall dam in Ticino, Switzerland.

Climbing up the Diga di Luzzone requires climbers to use a ladder to get up the first 20 feet of the wall, a feat that one climber will never forget.

“Obtaining the ladder to access the route and then having to put it away while on the route was an experience not to be forgotten,” said Ilana Marcus, a climber from Germany who ascended up the dam’s walls, told Caters News Agency.

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For Marcus, it wasn’t just the start that was unforgettable, it was also the reaching the top of the five-pitch climb.

“Topping out the climb to an audience of tourists watching your every move and perhaps anticipating the possibility of an exciting fall was quite memorable,” explained 31-year-old Marcus. “ Usually I climb in remote places, where the only cheering is in my head, so it was a pleasant change to have a group of people just as excited as us climbers.”

With the wall’s exposure to the elements, climbing the dam is similar to scaling up an actual mountain. Once climbers arrive at the top, they are also greeted with incredible views of the Alps.