Eagle is a 22-metre long impact crater located on the Meridiani Planum extraterrestrial plain, situated within the Margaritifer Sinus quadrangle portion of the planet Mars. The Opportunity rover came to rest inside Eagle crater when it landed in 2004. Scientists were delighted that the rover landed there, as the crater contains rocky outcroppings that helped prove that Meridiani was once an ocean floor. (wikipedia entry)
A crater is a circular depression likely created by an impact event. On Mars large craters are named after deceased scientists, writers and others who have contributed to the lore of Mars. Small creaters (less than 60km) are named after small towns and villages.