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
Sagan Planet Walk Sagan, Bill Nye, narrated a podcast tour of the Planet Walk in 2006 which can be accessed free by calling 703.637.6237 as you walk through the scale-model representation of the Solar System. The models of the Solar System, in order: The Sagan Planet Walk has inspired the creation of other scale-model Solar Systems in the United States. Sagan Planet Walk The Sciencenter's Sagan Planet Walk is a walkable scale model of the Solar System, located in Ithaca, New York. The model scales the entire Solar System—both planet size and distances between them—down to one five billionth of its actual size.