Cairn na Chullain
Cairn na Chullain is the tomb of Cu Chullain.
The Banshee made it her home in the 1990s, and kept Goliath, Elisa, and Angela here as her prisoners. The Gae Bolga was also kept here, until Rory Dugan came to the Cairn to claim it, and, in so doing, rediscovered his heritage as the reincarnated Cu Chullain. ("The Hound of Ulster")
Behind the Scenes
Greg Weisman has pointed out a missed opportunity in "The Hound of Ulster" that "really drives [him] crazy". Specifically that Cu Chullain's armor and bones should have been in the chamber of Cairn na Chullain where Banshee imprisoned Elisa, Goliath, and Angela.