Stonehenge in Wilshire England has existed as a solar calendar for over 10,000 years. The current stone structures were erected around 5000 years ago. Access to the monoliths was restricted by the English Heritage Commission in 1977, although I can recall visiting the epic steles with a British friend in the 1990s.
Few tourists were on the site. AJ and I looked at each other and shrugged wordlessly that laws were for other people. We wandered amongst the squat stones and no one said anything about our incursion. Times were different in the last century, however the same laws against approaching Stonehenge is in place for its replica Foamhenge iN Virginia.
Foamhenge is a full-sized replica drawing thousands of visitors to Natural Bridge, VA according to Wikipedia.
Sadly foam doesn't weather as well as stone and some of the monuments have cracked in half.
Others must be supported by wooden supports once more proving that they don't build them like they used to.