If you are familiar with google maps and google earth, then the next venue for your is the Google World Wonders Project. The project covers six continents (including Antarctica) and focuses on natural as well as manmade wonders. You can walk through the ruins of Pompeii, swim at the Great Barrier Reef, stand in the middle of Stonehenge, fly through the Grand Canyon, and more.
The Education provides lesson plan ideas for teachers of K-12 students. It’s a great way to incorporate these sites in your social studies and science curriculum.