The Halliwell Manor is a Victorian style manor on Prescott Street in San Francisco, owned by the Halliwell family. The manor has been home to several generations of Warren witches. The manor was built in 1898 by Edmund Baxter, only to be destroyed eight years later in 1906 by an earthquake. It was then rebuilt. The manor was destroyed a second time in 2006, during the Ultimate Battle, but this undone when the timeline was altered.
The Book of Shadows is kept in the attic of the manor, where it magically protects itself from evil.
A Nexus is a neutral focus point of spiritual and magical energy, located in the center of the five elements of earth, fire, wood, metal and water. The magic of a Nexus can be used by either good or evil, depending on whoever has control of it. A Nexus was located under the Halliwell manor, which was why the manor was built on that exact spot. With the Nexus under their control, it became an incredible power for good, which is why most evil beings never dared a direct attack on the sisters.
The Nexus was destroyed in 2005 by the Charmed Ones, who used it to vanquish Zankou, a powerful demon who had taken over the manor and had claimed the Nexus for himself. The Nexus was restored in 2029 by the Halliwell cousins.
A demon consisting of black shadow-like smoke, nicknamed the Woogyman by Phoebe, was at one point banished into the Nexus by Penny Halliwell. The Woogyman then somehow merged with the Nexus, causing it to be referred to as the Shadow.