At first, new recruits to Mostar's "Divers Club" are not allowed to jump from platforms higher than 6 meters. Gradually and under strict supervision, they jump from 8, 12 and 16 meters while learning proper techniques from other members.
The Club's crown jewel is the Stari Most (translated: "Old Bridge"). A 24-meter-high 16th-century UNESCO World Heritage Site and the main reason tourists visit the Bosnian city. The most experienced members of the Club collect money from spectators and then jump from the center of the arch.
One traveler from the group I was accompanying jumped from the Club's 12-meter training platform next to the bridge, landed wrong and broke a vertebra in his back (thankfully, he's fine now). After calling an ambulance, I spent the next two days in the hospital navigating the dysfunctional Bosnian health care system to pay his bill and get the proper documents for his insurance. Risky activity...