Chimborazo, an inactive stratovolcano, is Ecuador's highest peak. Its last eruption is thought to have occurred some time in the first millennium AD. Its summit is generally regarded as the spot on the surface farthest from the center of the Earth, at a distance of 3,967.1 miles. Chimborazo is a very popular climb and can be climbed year round with the best seasons being December-January and July-August. The easiest (Grade: PD) and most climbed routes are the Normal and the Whymper route. Both are western ridge routes starting at the Whymper hut and leading via the Ventemilla summit to the main (Whymper) summit. There are several other less used and more challenging routes on the other faces and ridges.