What you see here is a TAKRAF RB293 bucket wheel excavator. It's a big machine alright -notice the tiny little people in the lower right corner! But there are other machines even bigger, made to move mountains, dig tunne...

This Erie Steam Shovel Type B was built in 1925. It's not ready to retire yet. Here it is moving dirt at the International Plowing Match in Teeswater, Ontario in 2008. Link -via New Jovian Thunderbolt...