For those of you that may not know, the latest addition to the Overwatch roster, Sombra (currently available to play in the Public Test Realm on PC) has a teleport ability. By throwing her translocator device, she can zap herself to wherever it lands on the map. Some enterprising players have discovered that if you create a custom game and turn off the ability cooldowns, you can do some pretty cool things by chaining teleports together over and over very quickly. One player, Hoshizora, found that the trick could be used to break through the game's usual boundaries to travel all the way to the top of the skybox. The result is breathtaking.
Here's a short video showing how it was done, so you can try it for yourself. Though this video shows the trick being performed on Temple of Anubis and Hanamura, it actually works the same way on every map in the game (right now, at least, until Blizzard patches a fix.)