Newgrange was a 5,000-year-old Megalithic tomb located in Co. Meath, Ireland.
In (or at some point prior to) 2005, Gerard Shannon visited Newgrange with a group of friends, whereupon they witnessed the Ninth Doctor and Rose Tyler emerge from the tomb, both of them looking a little tired and worse for wear. The Doctor was telling Rose not to worry about something, assuring her that "They're trapped down there for another 5000 years!", with Gerard assuming that the Doctor and Rose were both archaeologists.
Gerard would later write about this encounter on the conspiracy website Doctor Who?, adding that, after reading the other information present on the site, he was no longer confident in his initial assumption. (PROSE: Have You Seen This Man?)