The European Sapce Agency (ESA) is an intergovernmental organization dedicated to the exploration of space [].
Besides its satellite navigation programme Galileo, it carries several remote sensing missions. Proba-V (monitoring vegetation as a SPOT-5 successor), ENVISAT (monitoring ecosystem activities from 2002 until 2012) and Sentinel (multispectral mission similar to Landsat starting 2015) are few examples.
ESA Link to Earth Observation (c.f. World) is a platform provided by ESA allowing to download some of the above named and even more products.