Stone of the Pregnant Woman, Ba'albek, Lebanon. Until recently, this was the largest known cut stone block in the world. Estimates range from 1000-1400 tons. That's up to 2.8 million pounds.
More recent photo. Block from the first pic is the one on top. It is sitting on top of two more giant blocks that are even larger, estimates range between 1400-1800 tons, or up to 3.6 million pounds.
Stone of the South. Somewhere between the Ba'albek quarry and the Ba'albek ruins, like it was in the process of being moved but something caused the work to stop, and it was never started back up. The lines and notches in the block are from people much more recently using the block itself as a quarry.
The Unfinished Obelisk at Aswan Quarry, Egypt. This is the place where a lot of the high-quartz-content granite used in many ancient monuments in Egypt came from, the famous "pink granite" of Aswan. This obelisk is enormous, as can be seen by the size of the people standing on it. It is more than one third larger than the largest known standing obelisk.
Yangshan Quarry, China. This is one of three gigantic objects in the quarry, supposedly parts of a stele that was going to be erected in a nearby city but these were abandoned as being far too large to be actually moved. We find this very hard to believe. That is a lot of work and a huge mistake, no pun intended.
Another part of the "abandoned stele" in Yangshan Quarry. Seems like somebody should have figured out "this is waaaaaay too big guys" long before they did so much work. You know?
Huge unfinished Moai at Easter Island.
Some of the enigmatic stone spheres of Costa Rica. The large ones are more than 8 ft. in diameter, and they are all geometrically perfect spheres.
The weird crystal cube bowl gear thingies from the Giza plateau.