A view just inside Popcorn Cave near Fall River Mills, California.  This lava tube is accessed through a small collapsed sink & has a few different passages though the longest tunnel goes no more than 100+ feet in.  The cave (as well as nearby Big Cave) were more popular in past decades however access to them has been left unmarked & overgrown in a buckbrush/ghost pine setting.  Both caves have abundant coralloids looking like popcorn, a type of speleothem to which the cave is likely named.  Smooth pahoehoe through a passage a few feet high leads one to a small pit which doesn't go any further.