No need to call authorities if you see a group of climbers marching up the arch of Sydney Harbour Bridge in Australia. Interest in scaling the arch was so strong, there’s a tourism company that takes groups up the southern stretch of the arch. Before the climb was sanctioned by the government, a few daredevils scaled parts of the bridge illegally. But now, it would be tough to do without running into a group of brave tourists on a walk up the arch.