The Spree is a river that flows through the German states of Saxony, Brandenburg and Berlin, and into the Czech Republic. It is a left bank tributary of the River Havel and is about 250 miles long.
In Buddhism, a boddhisatva is an 'enlightened' or a 'heroic-minded' being. It is someone who has achieved enlightenment themselves, but has elected to remain in their current state in order to help others achieve it.
Atlantes (sing. Atlas) are support columns or pillars carved in the form of a man, popular in classical European architecture. The female form of an atlas is a caryatid.
Unlike caryatids, which are usually graceful and effortless, atlantes are typically depicted showing great effort, with heads bowed and forearms lifted.
The name derives from Atlas, the Titan forced to bear the Heavens on his shoulders forever.
This reference is another inaccuracy, though most likely a deliberately ironic one. The term Ground Zero here refers to the hypercentre of an atomic explosion, and was first used by those involved in the Manhattan Project. It was therefore not in use before 1945, making it anachronistic at this point in Gravity's Rainbow.