"a vast velvet tent like the baldachino at St Peter's"
The baldachin at St. Peter's Basilica
Public DomainThe baldachin at St. Peter's Basilica - Credit: Mattana, Wikimedia Commons

A baldachin (It. baldacchino) is a canopy over an altar or a throne. It is sometimes made of cloth, but in cathedrals it may be a permanent architectural feature, in which case it is often known as a ciborium.

St. Peter's Basilica is a church located within the Vatican in Rome. It is considered one of the most holy of Christian sites.

The St. Peter's baldachin is a striking, highly-ornate structure designed by the sculptor and architect Gian Lorenzo Bernini.