The Underworld

The Underworld is a map which has an overpopulation of Skeletons and Zombies. Most blocks are Sand, Soul Sand, Stone and rarely Ores of all kinds. To go to the Underworld, you need a Soul Sand made portal. In this world, you'll meet the Skeletron Boss and Skeletons are Neutral and Teamworking like Zombie Pigman. But Zombies are still Hostile.