The study of explorers can be used to stimulate a lot of student interest and has a foundation for some excellent integrated lessons plans that involve science, technology, geography, culture, history, and language arts as well as art.
Exploration in the news makes it a good tool to use for teachable moments as well as cause and effect relationships.
Here are some of the best links I have found.
A list of sites that have free printable maps
A short biography on a huge number of explorers from early to space exploration is covered. For elementary use.
A general link site to explorers with the emphasis on North America
The Conquest of North America
Slow loading, but worth the wait
This site has both a list of explorers and countries explored. Good links and activities.
A large link site
Explorers as an integrated theme.
For grades K-8
A good site with the emphasis on the ships. Don’t miss the activity section.
An encyclopedia approach
This has explorers listed in alphabetical order with links.
Explorers by period and location
Very complete site.
Lessons and printables
Solar system exploration
How to become an astronaut
Excellent site for advanced thinkers
Space exploration and the problems it represents.
The Unconventional Explorer
Interesting site that offers lesson ideas on a variety of lesser-known explorers as well as the usual.
Compare and Contrast Explorer traits