The Atlantic Ocean, the Atlas Mountains, books of maps, architecture and statues, vertebrae and legendary islands are all connected by Atlas, the titan who appears in a wider variety of fields than perhaps any other character from ancient Greek myth.
Lee Lawrie, Atlas, 1937, Rockefeller Center, New York — Source: cmiper.com
In the myth, Atlas is one of the first gods, the Titans, who fight against the new gods, the Olympians led by Zeus, to decide who will rule the world. The Olympians win, and Zeus punishes Atlas by sending him to the western edge of the world to hold up the sky on his shoulders.
Vase with Atlas and Heracles, c.480 BC, National Archaeological Museum, Athens
For the Ancient Greeks, the western edge of the world was the north coast of Africa, starting in the area that is Libya and Tunisia today, so everything there was related to Atlas for them.
Naturally, they gave the name Atlas to the massive mountain range that starts in Tunisia and goes all the way to the ocean on the coast of Morocco in the west, even creating a myth according to which these mountains are Atlas himself turned into stone by Perseus with the head of Medusa.
Atlas Mountains (red) on satellite image — Source: commons.wikimedia.org
Also naturally, they gave the name Sea of Atlas, in Greek Atlantis Thalassa, to the ocean at the western foot of the Atlas Mountains, which has given us the name Atlantic Ocean, and because a powerful ancient island was supposed to be in that area, Plato called it Atlantis.
In the oldest known statue of Atlas, which is a Roman copy of an older Greek statue, the sky is represented as a sphere with a map of the stars and constellations known to the Ancient Greeks, which they represented as objects, animals and mythological creatures and characters:
Farnese Atlas, 2nd century, National Archeological Museum, Naples
Because of the sky map, and perhaps because it looks like Atlas is holding the Earth, 16th-century map-makers started using the image of Atlas holding a globe to decorate their books of maps. Here is the first example in history, at the top of this title page:
Antonio Lafreri, Tavole Moderne Di Geografia De La Maggior Parte Del Mondo Di Diversi Autori, 1572
By association, an “atlas” became a word referring to a book of maps. Also by association, a column with a male statue holding up part of a building is known as an “atlas” as well, and so is the vertebra that holds the skull at the top of the spine.
Atlantes (plural of Atlas), at 116 rue Réaumur in Paris — Source: fr.academic.ru
Atlas Vertebra Diagram — Source: ffcpc.org
So if you see a statue or image representing a male figure holding up something big and heavy, it’s probably Atlas, the titan who was forced to hold up the sky and whose name is still used today in geography, architecture and more.