The word of the day is massif:
< Middle French, French massif
A large building, or a range of buildings regarded as a single block.
Also: a mass of masonry or rock. (In later use generally understood as a
fig. use of sense 2.)
2. A very large topographic or structural feature in the landscape; esp.
a prominent mountain mass or compact group of mountains (usually
composed of older, more resistant rock than its surroundings), which
dominates an upland area. (OED)
"Hilu narrowly escaped capture, and he and thousands of his followers fled to live in the wilderness, many of them in caves in the spectacular stone massifs of South Kordofan: the Nuba Mountains."
- Jon Lee Anderson, "A History of Violence", The New Yorker 23 July 2012