The Alps may be more famous, but the Pyrenees have been around much longer – tens of millions of years longer, in fact. These mountains formed between 100 and 150 million years ago when the landmass that Spain occupies pushed into the one that France occupies. The mountains have served as a natural barrier between the Iberian Peninsula (Spain and Portugal) and the rest of Europe ever since. Stretching east to west across 430 sq km (166 sq mi), the Pyrenees fall mostly within Spain's borders, but also pass into the independent state of Andorra. The NASA Terra satellite captured this image of part of the Central Pyrenees – the highest part of the range – on 1 August 2000. In this false-color image, clouds appear white, snow appears pale blue, vegetation appears green, and bare ground appears as either pink or dark, bluish-purple. Water on the ground appears dark blue (or nearly black). In this shot, the vegetated areas are mostly to the north, and the peaks to the south are mostly bare rock. Patches of dark purple that are visible along rivers and in valley floors are probably developed areas. Image courtesy of NASA.