jeno passes along this excerpt from New Scientist:
"A deep hole on the moon that could open into a vast underground tunnel has been found for the first time. The discovery strengthens evidence for subsurface, lava-carved channels that could shield future human colonists from space radiation and other hazards. ... The hole measures 65 meters across, and based on images taken at a variety of sun angles, the hole is thought to extend down at least 80 meters. It sits in the middle of a rille, suggesting the hole leads into a lava tube as wide as 370 meters across."