
The well. It is a collapsed sinkhole formed when underground waterflows eroded the overlying strata, forming a cavity. When the cavity grew big enough to not be able to support the top, it fell down, leaving a water-filled hole in the middle of the desert.
2006-04-09 15:52

The hole seen from the opposite rim. Note the houses built into the wall - it was a popular way among the people living here of building houses that were well-protected and warm.
2006-04-09 15:56