Floo Powder

From Hpwiki

Floo Powder is used in the wizarding world to travel very fast. But this traveling is - by origin and destination - restricted to places with wizard households which of course all have chimneys: You spread some of this powder into a chimney fire. When the flames burst up in emerald green, you step in and say the name of the destination, loud and clear. Then you pass through many chimneys along the route. It's your own responsibility to step out at the proper time.