Go to the University of Florida Smathers Library site, and admire the beauty of these old maps of Florida and the Gulf of Mexico. (While I think fair use would cover it, I’m holding back on posting an image until copyright permission comes through — you’re licensed to use them in the classroom, however.)
The maps featured on the first page include Spanish, Dutch, English, Belgian, French and Italian maps of the early explorers, suitable certainly for Texas history courses, and also for Florida, Louisiana and U.S. history units on European exploration.
This site is quite Florida-centric, but it’s links also provide some interesting and valuable resources, such as the link to satellite imagery of the areas, like the NOAA map, below.
Tip of the old scrub brush to A Cracker Boy Looks at Florida