A heavily guarded chamber at the center of Asgard's Palace, the Weapon's Vault is home to many of Odin's exotic vaulables. Odin captured and stole and purchased and did whatever he could to take all the relics and weapons that could bring about Ragnarok (the Asgardian end of times), and he locked them away in a vault in the base of his palace, so anything he thought could bring the universe down is now under lock and key.
Home to the incredibly powerful Casket of Ancient Winters, the Weapon's Vault has always been a prime target for those seeking powerful weapons of destruction. During Thor's crowning ceremony, the Vault is attacked by three Frost Giants attempting to steal the casket. However Odin sensed the Frost Giants in the Vault and activated the Vault's deadliest automaton device Destroyer to dispatch the the Frost Giants.
The Vault houses not only the Casket of Ancient Winters but other vastly powerful objects such as:
The Eternal Flame: Mystical flame that cannot be extinguished. It was stolen from Surtur by Odin, Vili, and Ve Borson at the dawn of time so that Surtur could not light his sword and bring about Ragnarok.
The Warlock's Eye: A powerful, mystical weapon used unsuccessfully against Odin, Thor, and the Warriors Three during an invasion against Asgard.
The Infinity Gauntlet: the Infinity Gauntlet was designed to hold six of the 'soul gems', better known as the Infinity Gems. When used in combination their already impressive powers made the wearer nearly invincible. It was later revealed by Hela that the Gauntlet kept in the vault was fake.
The Tablet of Life & Time: On the tablet was a biochemical formula for a serum, the so-called Lifeline Formula, which could rejuvenate, heal, and grant its user the chance to reach the full evolutionary potential of its race turning the user into an immortal near omnipotent.
The Cosmic Cube: It is also believed at one point to have housed the Tesseract before it was later located on Earth.
Information about page was taken from the book The Art of Thor.