Stop walking across a dark room to turn on the light. Install a 3-way switch and control lights from two locations.

In the diagram on the link they are using a three conductor cable after the first three way switch. Black, Red, and White with a separate ground.

Here's how to swap outdated three-way light switches for something much better.

Below, Donnelly tells AD how to wire a light switch with this simple step-by-step process for a single-pole light switch without zapping yourself along the way.