In Minecraft forums, a user may post a seed code to a jungle or desert temple confusing it for a castle. Castles do not spontaneously exist in Minecraft. They must be built by the user. Temple seeds are shared by users in Minecraft forums.
A Minecraft seed is a randomized string of numbers that generates each time a user creates a new world. It is that world's particular code. Since no two worlds created in Minecraft are ever the same, a user can share the seed code to help other users create the same world they have.
Minecraft users love to share interesting seeds. Minecraftseeds.co has compiled and tested interesting seeds submitted by users for the many versions of Minecraft. Users choose to share seeds that are visually stunning, contain rare biomes (such as a mushroom biome spawn), lead directly to helpful villages for an easier start or worlds that contain easily accessible loot.
To use a Minecraft seed, write down or copy the chosen seed code. Launch Minecraft and choose "create new world" from the startup menu. Choose "more world options" on the following screen. Enter the seed code into the "Seed for the world generator" box, including any negative signs at the beginning. Select "create new world" after entering the seed, and wait for the chosen seed to load.