Trondheim is a city and municipality in Sør-Trøndelag, Norway, that is home to DORA 1, an ex-U-boat base that now houses the city and state archives.
While investigating the lost treasure of Sir Francis Drake, Nathan Drake visits the DORA 1 achieves in Trondheim, specifically to view the Kraus collection. The collection contains information on Sir Francis, and it apparently gave Nathan even more reason to suspect that his ancestor had a large, hidden stash of Spanish gold. Elena Fisher hired an investigator to track down Nathan, but s/he arrived too late; after gaining access to the archive, they found a letter from Nathan and a flyer for a Sir Francis Drake exhibition at the Rijksmuseum in Amsterdam, Netherlands. Combined, these clues led the investigator to Amsterdam.