This achievement requires that you damage 5 blocks of the tower with a single use of the Fire ultimate power, Meteor Shower. Having the Meteor Shower power upgraded to three stars will make this easier, but is not a requirement. This can be done on pretty much any Campaign or Survival level. Just let the workers build the tower up to near completion. Then call the attack near the top of the tower. With any luck, it should destroy five or more blocks of the tower and unlock this achievement immediately. If it doesnt unlock, just load up a new round and try again.