The Subway
Track going across the map, a little ways down. Keep digging and you'll hit it.
Haunted Graveyard
I recreated the shrine (or temple) structure from the last screenshot on the Steam store page for Terraria. Not an exact copy, but it does summon angry spirits. Well... angry wraiths if you want to be specific.
SUPER SWORD SHRINES
You may have just won yourself an Arkhalis! Many chances to wield one of the rarest and unique weapons in the game! Results not guaranteed.
Old One's Arena
A quickie arena near by the spawn point.
Jungle Arena
A perfect location to pick a fight with a giant plant.
Good place to call home
The spawn point is located right next to some interesting land features that are perfect for a floating base. Very Secure!
Title
This is totally not in this world. Just a title screen.
Pearlwood Island
Up in the sky somewhere. Try out a Pearlwood set before hardmode. It's surprisingly not bad!