The giant stones of Baalbek
The account
Blocks weighing nearly a thousand tons at the base of a temple would be too heavy for any ancient people: the work of giants or of visitors.
What investigators found
The Temple of Jupiter is Roman. Tool marks in the nearby quarry and Roman engineering with levers and winches explain the work, impressive as it is.
The story
In Lebanon's Bekaa Valley stand the ruins of Baalbek, one of the largest building projects of the Roman Empire. At the base of the Temple of Jupiter sit three stone blocks, known as the Trilithon, each weighing about 800 tons. In the quarry next door, the "Stone of the Pregnant Woman" still lies on the ground, at close to a thousand tons. In 2014, German archaeologists found another block beneath it, even bigger.
To ancient astronaut proponents, the platform is far older than the Romans, built by a lost civilization or with outside help. Archaeologists point out that the quarry bears Roman tool marks and that the giant blocks left behind show exactly that: work in progress. How they were moved is still debated, but everything points to engineers of the 1st century BC.