1. Caves! By Lily Ann Ellingson

2. What they are • Caves are hollows and tunnels in a mass of rock that have been carved out with water. • They usually are made of calcite or limestone. • Stalagmites and stalagtites are formed when water carrying dissolved calcite repeatedly drips and evaporates leaving a tiny amount of calcite each drip, but eventually it builds up • Fun Fact: Demitri Martin just calls them all stalags because it sounds more chill, and he can’t remember which is which.

3. Reed Flute Cave in China • http://famouswonders.com/reed-flute-cave/