Another thing that is cool about going to the national monument is that you do not even have to make a reservation! There is about twenty caves that you may explore without even making a reservation. Is that not awesome? Of course there is more caves, but for those you do absolutely have to make a reservation. There is about 27 caves that have different challenges for you. You can have the least challenging, the moderately challenging one, or the most challenging ones of all! These caves were formed thousands of years ago about 10,500 to 65,000 years ago by the lava tubes there. As the lava begin to flow down it started cooling down and solidify on the top and on the sides. Once the eruption stoped and the tube emptied and drained a new lava tube cave was formed! Then it began making cracks and collapsed making the open