Elfheim is an exploration map: a map within which players can start anew and play through a regular Terraria game, except one filled with unique and fun things to discover. There are no rules to follow, and no restrictions to abide. Make a new character and keep your starting gear, just as you would in a normal Terraria map, and get ready to dig, fight, and explore with the best of them! In Elfheim, you can craft or find any and every item, explore any and every biome, and fight any and every boss. The whole of Terraria's gameplay is available to you.
What makes Elfheim unique is how full it is of custom content. I've constructed a number of player headquarters and other interesting builds all around the map. In addition to bases, you will also find a whole variety of treasure caches, shrines, altars, farms, and other such lootable bonuses hidden all over the underground. You will find examples of all these things included in the download.