Humboldt-Terrasse, Observation terrace in Salzburg, Austria

Humboldt-Terrasse is a stone viewing platform on the eastern side of the Mönchsberg, set above the Klausentor gate between the Old Town and Mülln. It is not at the summit: a stone staircase leads down from the path between the Museum der Moderne and the Müllner Kirche to the platform, where a plaque carries the Humboldt quotation. The view corresponds to that from the busier points near the museum and the Müllner Schanze.

Prince Archbishop Paris Lodron built this platform in the 17th century during the Thirty Years' War as part of the city's defensive network. It served as a strategic position for monitoring approaches to Salzburg.

The name comes from banker Karl Leitner, owner of Schloss Mönchstein, who opened the Klausenkavalier in 1896 and had the Humboldt inscription placed here in 1897, a century after Humboldt's stay. The supposed Humboldt quote about Salzburg, Naples and Constantinople first appeared in 1870 in Heinrich Dieter's guidebook; no letter by Humboldt has ever been found, and he never visited Constantinople.

The easiest approach is through the path connecting the Museum of Modern Art and Müllner Church, which leads across the former gun platform. The route is straightforward and clearly walkable from the lower town.

The plaque's supposed Humboldt quote ("Salzburg, Naples and Constantinople are the most beautiful regions of the earth") first appears in the second edition of Heinrich Dieter's Salzburg guide in 1870, decades after Humboldt's 1797–98 stay. No letter to Mielichhofer has ever been found, and Humboldt had not yet visited Naples and never went to Constantinople. Banker Karl Leitner, owner of Schloss Mönchstein, had the platform opened in 1896 and put up the plaque in 1897.