The Landsat program has been capturing satellite imagery of the Earth since the early 1970's. This means that we have access to over 40 years of satellite imagery, which is a wonderful resource for documenting changes to our planet.
Landsat Lens allows you to explore how the Earth has changed by allowing you to compare Lansat satellite imagery from six different years. The map allows you to search for any location on Earth and then overlay satellite imagery of your selected location from 1975, 1990, 2000, 2005, 2010 & 2015.
For example the screenshot above shows a map of the Aral Sea with four different satellite images from four different decades. Being able to directly compare satellite images from different decades in this way really helps to highlight the scale of how quickly the Aral Sea is disappearing.
Other locations around the world that have seen drastic changes over the last few decades can be viewed using the quick links in the map sidebar.
The School of Geosciences at Sydney University has released the first interactive map of seafloor geology. Seafloor Lithology allows you to explore seafloor lithologies based on nearly 14,500 samples taken from the world's seas and oceans.
Seafloor Lithology includes three different map views: an interactive 2d map, an oblique map projection (which allows you to view seafloor elevation) and a 3d Cesium globe view. The 3d globe view also allows you to explore the topography of the seafloor in 3d (use ctrl & the left mouse button to rotate the camera view around a point).
The map key explains the colors used for the seafloor's different geologies. The map key is a little small but if you click on the key it will open in a legible size in a separate window.
Cities at Night is an attempt to collate and share night time images of the Earth captured by astronauts aboard the International Space Station.
A major part of Cities at Night is a citizen science project in which anyone can help identify the exact locations depicted in photographs by ISS astronauts. By contributing to the project you can help to build a better map of worldwide light pollution.
You can view some of the already geo-located photos of the Earth at night on the Gallery of Interactive Maps. The gallery includes a number of maps of major cities in which ISS night-time photos have been overlaid on top of a map of the cities. For example in the screenshot above you can see the huge amount of light pollution in the city of London.