A View on Cities
This is a nice site that gives you the chance to look up information about many large cities around the world. You can look at photos, maps, building information and much more.
History.com's 7 Wonders of the World
An interactive map that shows the wonders of the world and allows you to click on them to get some information.
PBS Building Big
This site has a lot of information about many great buildings and structures, including many wonders of the world.
Here is a great site to learn about the wonders of the world. There is also a link for a world atlas.