Comparing The Planets

Volcanic landforms are found on all of the terrestrial planets and on the Moon. The most distinctive volcanic features are the smoldering craters of active volcanoes on Earth or the immense Olympus Mons on Mars. However, ancient volcanism occurred on the Moon and perhaps Mercury as well.
Olympus Mons, Mars 57k JPEG NASA Image P-37657 processed by the U.S. Geological Survey	Mt. St. Helens, Earth 182k JPEG USGS Aerial Photograph

Sapas Mons, Venus 107k JPEG NASA Magellan Image	Lava Flows in Mare Imbrium, Earth's Moon 113k JPEG NASA Image Apollo 17 #AS17-155-23713
(note: each of the above images (and therefore features) are at different scale)