From the PDF Introduction
A Web Enhancement for the Planar Handbook
The Planar Handbook describes extraplanar locations suffused with the power of all existence that are known as planar touchstones. Characters linked to these natural hubs of planar activity can tap their power for personal use, gaining abilities that reflect the nature of the specific locations. But gaining power from the planes is not without risk, and those wishing to exploit their planar connections to the utmost must brave the dangers of the touchstones with which they are linked.
Dozens of planar touchstones are described in the Planar Handbook, complete with abilities gained and specific perils of the locations. Now designers Bruce Cordell, Gwendolyn Kestrel, JD Wiker, and Skip Williams offer four additional planar touchstones for plane-hopping PCs to exploit.