Lava Beds National Monument Stronghold, which is 450,000 years old. Petroglyph Point was created about 275,000 years ago when cinders erupted through the shallow water of Tule Lake; violent explosions of ash and steam formed layers upon layers of tuff. The caldera is thought to have formed by subsidence, during which basalt and andesite were erupted up on the slopes. Lava flows dated to about 30,000–40,000 years ago formed most of the lava tube caves in the monument. As the hot basaltic lava flowed downhill, the top cooled and crusted over, insulating the rest of the lava and forming lava tubes. Lavacicles on the
The floor is lava The floor is lava The floor is lava (also known as hot lava) is a game in which players pretend that the floor or ground is made of lava (or any other lethal substance, such as acid or quicksand), and thus must avoid touching the ground, as touching the ground would "kill" the player who did so. The players stay off the floor by standing on furniture or the room's architecture. The players generally may not remain still, and are required to move from one piece of furniture to the next. The game can be played with a group or