The Skull Throne is a stone throne about 6 foot tall with two skulls on the top left and right. Traditionally it sits inside the skull cave in the main entrance right in the middle on a stone slab with steps leading up. Along each side of the throne are tall fire pits.
In some Lee Falk stories the throne has been outside of the Skull Cave as well. However the throne needs to be inside and not outside. (Below are examples of the Skull Throne outside by Ray Moore and also Sy Barry).
The first Phantom like the Skull Cave has been modified by the first Phantom. Some Team Fantomen & Frew creators add the Good Mark on the face of the throne under the arm rest.
The 20th Phantom added a chain to the throne to be used as a reminder of having patience. After the Lee Falk story (Sunday 34 - 1953) it was not shown again in any Phantom story until a 2007 story. Although not used, phans love it and we would recommend every time the Skull Throne is shown from the 20th Phantom onwards it is shown. You can read an article on the full history of the chain here.
Phantom Wiki URL