Sinnoh Underground

The Sinnoh Underground is a huge network of tunnels that run underneath the region of Sinnoh. Once you reach Eterna City and obtain the Explorer Kit item from the Underground Man, you can enter this huge area. He sets you different challenges to complete in the Underground. These range from digging for spheres to making and decorating your own secret base.

Spheres are the currency of the Underground. Spheres can buy you anything, from traps to treasure and even items to decorate your secret base. If you bury spheres in front of you and leave them there after a while they grow larger. If you bury a lot of spheres of the same colour in front of you and then dig it up a larger sphere is obtained. You can also find fossils, which can be restored in Oreburgh City, Heart Scales, which are to give to the Move Tutor so he can teach your Pokemon other moves that it has learned by levelling up. On the floor, traps can be picked up. People can play together using DS wireless communications in Sinnoh Underground. They can steal flags from each other's secret bases to upgrade thier own. They can also interact and "chat"

This is a inprovement on the pokemon games.You can go down there anywhere you like.You can bring up treasure up from the underground and somtimes sells it