Goliath

During your playthrough you will accumulate Treasure Maps. One final boss of a world I cant remember will also have a ton of them scattered around his arena for you to pick up (its where the majority came from for me). They appear as little scrolls in your inventory. Read them and if it says "This treasure is from a different world" it means you have to warp to any of the 3 other worlds and try again. Make sure you do this achievement before reaching the last world (it has only one area and once you are instructed to make a portal with 50 Iron bars and 10 Meteorite bars is when you get to it). If it says treasure added to map, pull up your map tab and look for an icon that resembles a compass from afar (if you are all the way zoomed in you will notice its actually a horned skull on a circular emblem). Get to the marker on the map and on the ground you will find a red X symbol. Dig it up and watch your achievement tracker move by 6 %. Now repeat this 14 more times.