Rescue workers on Jan. 29 were trying to retrieve the driver of a 2-ton truck that fell into a sinkhole at a prefectural road intersection here.

Inland blue holes, however, are unlike any other environment ... Many astrobiologists believe such conditions may exist in pockets of liquid water deep beneath the surface of Mars or in a sea ...

"We were holding on to a rope in 50-60ft (15-18m) deep water for at ... inside a so-called "rat-hole" mine - a narrow hole dug manually to extract coal - when water suddenly started flooding ...