Google's World Wonders Project uses Street View technology to take you on virtual tours around some of world's most historically significant places and monuments. Destinations include North and South America, Europe, Asia and Australia and you can browse them either by clicking and dragging in the globe at the bottom, or through the menus of the page.
Additional information is supplied for each site as well as photos and 3D models. It's a great way to visit world heritage sites that else you would never have the chance to see!
Here is a video explaining what World Wonders Project is
and here is an amazing behind the scenes video showing how all those images were captured and combined! It looks great working for Google!
Unfortunately I don't see Athen's Parthenon among the momuments. Anyway more sites are going to be added soon with the help of UNESCO and World Monuments Fund.