You should consider including Valle de los Callidos (Valley of the Fallen) in this list. The tomb of Generalissimo Francisco Franco, it is an entire cathedral carved in a mountainside and intended to be a monument to those who died in the Spanish Civil War. It was built by Republican veterans in virtual slave labor over a period of 18 years. It's topped by one one of the largest stone crucifixes in the world -- which of course, is positioned on the hilltop directly over the position of Franco's final resting place in the church below.