Today is the anniversary of Landsat 7's launch, marking 15 years and over 1.7 million images of our changing planet. Tour the US Geological Survey's gallery of favourite images, or browse the entire collection for free.

von Karman vortices, formed as winds are pierced by the towering Alexander Selkirk Island. Acquired by Landsat in 1999.

Check out more Landsat images in this before-and-after photograph pair of the Washington landslide, or learn how these types of images are used to monitorfloods and droughts around the country.