Touching the bottom of the world requires you to dig down the bottom edge of the world (the opposite of Icarus achievement). For beginning players, you will need to dig down into the Underworld. The best way to do this is to create a hellevator close to your home base.MAKING A HELLEVATOR
1. A fast pickaxe is recommended since this will require a lot of digging.
2. Make a hole leading straight down, at least two blocks wide (I recommend five because you can add walls later and line it with material to keep enemies out).
3. Place platforms across at intervals to prevent falling damage, or bring some buckets of water and drop them at the bottom to make a little safe landing area.
4. Add some light sources.
5. You can make branches out to the sides (and add doors) to access underground areas for mining ore or exploring.
6. You can also make this go up into the sky if you are going for Icarus as well.
The further underground you go, the harder enemies become. Eventually you will reach "The Underworld", which has a black volcanic looking background with no walls. You need to make your way to the bottom of the screen. You must have a Demonic Pickaxe or better to mine the Hellstone down there or other materials
, but you can dig through the ash blocks if you want to go for it. This is the area where you throw in the Guide Voodoo Doll to summon the Wall of Flesh.
If you built a hellevator, then you can go into "The Underworld" and come back to the surface to get:
The To Hell and Back achievement in Terraria worth 85 pointsTravel from the Surface to the Underworld and back in one fell swoop.QUICK SOLUTION
***Same as 360 version***