 And they believe there are hundreds of these. They believe that the cave may have been created by a collapsed lava tube. How big is it? It's about 130 feet wide, 10 yards long. And again, they believe there could be hundreds of these pits and caves all over the moon. Scientists believe that going into those caves could help them better understand how the moon evolved, including its volcanic activity. By the way, it was this week in July of 1969...