Civilization:
Florida Trails- This is perhaps the best website that I have found for finding out the history of what buildings are in your city in Florida, as well as what used to be in towns as well. The site doesn't have any graphics, but the vast amount of information makes up for it.

Florida's Lost Tourist Attractions- Is all about the many tourist attractions in Florida that have closed up.

Roadside America- Read all about Florida's Roadside Attractions here.

Nature:
Springs Fever- This website is one of the best references I know of when it comes to natural springs in the state of Florida.