I've never played the map, but Aeon of Strife from Starcraft is a custom map that has the origin of Dota mechanics... and the Protoss Photon Cannon brought abou

I've never played the map, but Aeon of Strife from Starcraft is a custom map that has the origin of Dota mechanics... and the Protoss Photon Cannon brought about some earlier versions of Tower Defense custom maps.