This website has a lot of depth. Not only is there a charming little game in which the kids can dig up and assemble artifacts, along with several enjoyable activities, but there is also a lot of accessible, simply presented information. There are good photos included in each section, but you may not be able to watch the videos. They appear to be unavailable in the U.S.
This is a fun one to look through together, and reading aloud can help kids focus on one part at a time.
You could use the game as either a reward for paying attention or as an introduction to the site, the rest of which you can explore together once they have the game-playing out of their system. It depends on what works best with your kids, of course.
There are also many good suggestions included for other quality sites to visit.
