Geologic Time

The Mesozoic Era is called the "age of dinosaurs". The Carboniferous Period is famous for its coal swamps. The Precambrian was after the "explosion of Life". Humans first appeared, and the last ice age occured in the Pleistocene Epoch. Human life ended the Mesozoic Era. The time periods are in order from longest to shortest, period, epoch then era.
http://www.fieldmuseum.org/evolvingplanet/post/ep_v8.swf
Tour Through Time
http://www.ucmp.berkeley.edu/quaternary/ple.html
Geologic Time

Florida's Sinkholes

Sinkholes are caused by groundwater erroding limestone in the bedrock. Florida has so many of them because of it's karst topography. Sinkholes worsen in cold weather because it speeds up the errosion. Sinkholes can be hazardous because they can eliminate entire lakes.

http://plants.ifas.ufl.edu/guide/sinkholes.html
Sinkholes

Nashville Floods

The flooding in Nashville was caused by a torrential rain. The Cumberland River became 50 ft deep, which is 12 feet higher than before the flood. Before the flood, Nashville was protected by a levee. It didn't protect from flooding because it accidentally broke.
http://www.nytimes.com/2010/05/04/us/04flood.html?src=mv
http://abcnews.go.com/WN/nashville-flooding-29-dead-flash-flooding-south/story?id=10555626