It’s my understanding that Stonehenge was reconstructed in the mid 1950’s using cranes and concrete, thus hardly original other than the stones themselves.
Some of the original stones were tipping over, and were straightened. A similar process has been performed here and there on Easter Island for those big heads.
Debunked: Photos that “Prove” Stonehenge was Built in 1898 or 1954
http://wafflesatnoon.com/stonehenge-built-modern-times/