Corinne Vionnet sifted through online searches of the world's most recognizable tourist attractions in order to carefully layer 100's of photos of each on top of one anther until she created her desired result. Her site contains a few smaller ones which aren't available in the blog post, as well as some more information on the project. [more inside]
CyArk is a non-profit which makes three-dimensional scans of archaeological sites with lasers in effort to digitally preserve them. It currently has 27 projects, including Chichén Itzá, Angkor Wat, Anasazi Pueblos in Mesa Verde, Thebes, Rapa Nui and the Royal Tombs at Kasubi. There's quite a lot of material about Cyark online, including profiles Wired Science, a lecture by founder Ben Kacyra at Google as well as an article in Archaeology and an article by two CyArk employees in Professional Surveyor describing how they work.
Ancient observatories from space Satellite images of Angkor Wat, Chichen Itza, Chaco Canyon, Stonehenge, Teotihuacan, and others. The observers, observed. High res images available.