This picture shows two enormous volcanoes on Mars, Ceraunius Tholus and Uranius Tholus. Ceraunius Tholus is 130 km across and rises 5.5 km above its surroundings. Its neighbour, Uranius Tholus is a smaller volcano, at its base it is 62 km across and it is 4.5 km high.
Credit:
ESA/DLR/FU Berlin (G. Neukum)