Water on Mars carved deep gullies and left a 'great puzzle' for Red Planet history
Gullies on Mars may have formed when the Red Planet was highly tilted on its side, triggering dramatic shifts in climate that sent water cascading down slopes to carve out ravines.
TroibNews 
Gullies on Mars may have formed when the Red Planet was highly tilted on its side, triggering dramatic shifts in climate that sent water cascading down slopes to carve out ravines.
