If you only have time for one cave at Lava Beds, the rangers will point you at this one. Valentine is the cave that still looks like the day after the lava cooled.
The flow that made it erupted 10,850 years ago, which is recent enough that almost nothing has happened to it since. Its walls are smooth and oddly organic, and it carries what the Park Service calls primary volcanic features: the shapes left by moving lava rather than by anything that happened afterwards. In most lava tubes you are looking at a passage that has been rearranged by collapse and rockfall. Here you are looking at the tube itself, more or less as the lava left it, with flow lines along the walls and lava benches marking where the level of the molten river stood at different moments.
It is ranked among the least challenging caves in the monument, with relatively high ceilings and a smooth floor, which is why it is the usual recommendation after Mushpot, the short lit cave beside the visitor centre.
The monument sits on the northeastern flank of Medicine Lake Volcano, the largest volcano by area in the entire Cascade Range, and holds more lava tubes than anywhere else in North America. Twenty seven of them have marked entrances and developed access.
You need a caving permit before entering any cave here. They are free from the visitor centre, and they exist partly to brief people properly and partly to slow the spread of white-nose syndrome among the bats. Bring a helmet and more than one light. The floor is dark rock and the ceiling is closer than you think.
Other places on the map within a couple of hours.
