It's 5,500 years old and one of the most distinctive features of the Welsh landscape, but now the Pentre Ifan monument has been given the benefit of 21st Century technology.
Thanks to CGI we can now see what the original burial chamber in Pembrokeshire would have looked like.
The unmistakable stones are all that remain of the ancient site.
Now a video reconstruction shows how they were once a doorway to the chamber.
Historic monument body Cadw has been giving the CGI treatment to some of its sites, re-imagining what the likes of Caerphilly Castle and the Segontium Roman Fort in Caernarfon.
Ken Skates, deputy minister for tourism, said it was a way of bringing Welsh history to new audiences.
"The CGI videos have been viewed thousands of times online and we hope they will continue to encourage people to explore Wales's historic environment."
Designers worked with experts at Cadw, using detailed floor plans, site measurements, artists' impressions and mapping information for monument near Nevern.
The Pentre Ifan video is the final in the CGI series as part of Cadw's Time Traveller campaign.