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.
http://www.history.com/minisite.do?content_type=mini_home&mini_id=54814
PBS Building Big
This site has a lot of information about many great buildings and structures, including many wonders of the world.
http://www.pbs.org/wgbh/buildingbig/index.html
Wonder Club
Here is a great site to learn about the wonders of the world. There is also a link for a world atlas.