Seed : 5578892759289888053
Remember, with the release of the Minecraft version 1.12 Pre-Release 3, Mojang published this photo
You were several to ask for the seed, and Dinnerbone was kind enough to share it :-)
This mountain is located just next to the spawn point (on the spawn in the forest on the left of the image).
But besides this mountain that seems to arise out of nowhere, this seed offers another amazing landscape:
In the forest where one spawn, one discovers this amazing floating structure