Fort Salta

Fort Salta (スラトア要塞) is a Marleyan fortification and research base in the southern mountainous region of the continental mainland.

Structure
Fort Salta was constructed into a mesa which towers over a wide, arid landscape of scattered buttes and rock formations. It is connected via railway, which weaves between the surrounding buttes before spiraling up the face of the mesa to the top of the hill.

The summit of the mesa possesses extensive facilities, including facilities to maintain a sizeable fleet of military airships and to develop and test new airship models. Some of the smaller hills surrounding Fort Salta also contain structures at their summit.

War for Paradis arc
Upon arriving in Odiha, Yelena confesses to Armin Arlert and Levi Ackerman about a strategic meeting she held with Eren Yeager. She details a plan to cripple Marley's military forces with a partial Rumbling in order to secure Paradis Island's safety for several decades to come. After Eren's uncertainty of her plan to attack the Port City of Acirfa (to crush the Global Allied Fleet before it is ready) being a fully successful deterrent, Yelena voices her concern about Fort Salta's airship base being a potential threat. She deduces that, with Eren unleashing the full force of the Rumbling to raze the world, he would next target Fort Salta to prevent any resistance against the Founding Titan and its Wall Titans.

Not long afterwards, a train carrying survivors from Liberio approaches Fort Salta, where Annie Leonhart's father hopes to find an airship that the refugees can use to evade the Rumbling. Shortly after, they spot the the fleet of airships taking off, followed by arrival of the Founder's Rumbling. Initially despairing that they've been left to die, the Marleyan conductor then realizes the airships took off in response to the Titans' arrival, and are in fact a military squadron about to bomb the incoming Titans from an unreachable height.

Trivia

 * Unlike the majority of Marleyan location names which are based in Latin or Italian nomenclature, "Salta" simply appears to be "Atlas" spelled backwards. This is also applicable to the original katakana in which the characters for Atlas (アトラス) are reversed. This may refer to its location being, when vertically mirrored, analogous to the of northern.
 * Coincidentally, the name "Salta" still fits with the Latin and Italian nomenclature of Marleyan location names, as "salta" means "skip" in Italian, derived from the Latin "saltus".

Navigation
Fort Salta