Shield volcano Mars are very similar to the shield volcanoes on Earth. Both have gently sloping flanks, collapse craters along their central structure, and are built of highly fluid lavas. Volcanic features on Mars were observed long before they were first studied in detail during the 1976–1979 Viking mission. The principal difference between the volcanoes of Mars and those on Earth is in terms of size; Martian volcanoes range in size up to high and in diameter, far larger than the high, wide Hawaiian shields. The highest of these, Olympus Mons, is the tallest known mountain on any planet in the solar
Mons Massicus Mons Massicus Mons Massicus, a mountain ridge of ancient Italy, in the territory of the Aurunci, and on the border of Campania and Latium adjectum attributed by most authors to the latter. It projects south-west from the volcanic system of Rocca Monfina (see Suessa Aurunca) as far as the sea, and separates the lower course of the Liris from the plain of Campania. It consists of limestone, with a superstratum of pliocenic and volcanic masses, and was once an island; its highest point is 811 meters (2661 feet) above sea-level. It was very famous for its wine in ancient times.