Terraria – How many bee hives are there per world

You can go exploring some corrupted/crimson areas (randomly picked at world generation) to destroy the shadow orbs/crimson heart waiting for you at the bottom of chasms.

Each shadow orb/crimson heart destroyed will provide you some loot, and make a meteorite land on the world. Once the meteorite has fallen, go find the site, and mine the meteorite ore. This will allow you to craft some meteorite gear and weapons.

Once you've destroyed three shadow orbs/crimson heart, it will make the Eater of Worlds/Brain of Cthulhu spawn, allowing you to fight two different bosses.

Note: The shadow orbs are protected behind some ebonstone/crimstone, which you will not be able to mine with your current pickaxe. Just buy some dynamite from the Demolitionist and use it to access the shadow orb. Or you can buy purification powder from the Dryad, which turns the ebonstone/crimstone into the easily destroyable standard stone.

Pretty much all of the biomes (using Terraria's liberal definition of "biome") can be moved to another location, within certain limits.

The most extreme example is a Meteor crash site biome, which can exist anywhere, at any height. At the other end of the spectrum, we have the Dungeon, which cannot be moved at all.

Completely immovable

• The Dungeon, because it requires an unsafe background wall below the Dirt Wall depth (cannot be placed by the player).
• The Underworld, which is restricted to the very bottom of the map
• The Sky, which, like the Underworld, is just there at a certain altitude.

Mostly immovable

• The Ocean is not completely immovable, but very inflexible. It is both restricted to a certain height (above the surface level), and can only exist within 250 blocks from either edge of the map. You can create an artificial Ocean in the middle of the map, but that won't spawn Sharks, nor will it grow Corals. Creating artificial Oceans that sort of float above the real one does work; I have actually done so to farm Corals.