St Paul's is built in the shape of a cross, with a large dome crowning the intersection of its arms. At 111.3 metres high, it is one of the largest cathedral domes in the world and weighs approximately 65,000 tons. The area under the dome is the principal place for worship in the Cathedral.

St Paul's has a three-dome structure. This allows the inner dome to rise in proportion to the internal architectureand the outer dome to be much larger and impressive. It is this outer dome shell that is prominent on the London skyline. The inner dome is the painted dome one can see looking up from the cathedral floor.

The Whispering Gallery
Climb 259 steps up the dome and you will find The Whispering Gallery, which runs around the interior of the Dome. It gets its name from a charming quirk in its construction, which makes a whisper against its walls audible on the opposite side.

The Stone Gallery
The Stone Gallery is the first of two galleries above the Whispering Gallery that encircle the outside of the dome. The Stone Gallery stands at 173 ft (53.4 metres) from ground-level and can be reached by 378 steps. 

The Golden Gallery
The Golden Gallery is the smallest of the galleries and runs around the highest point of the outer dome, 280ft (85.4 metres) Visitors who climb the 528 steps to this gallery will be treated to panoramic views of London that take in the River Thames, Tate Modern and Shakespeare's Globe Theatre. 

The Ball and Lantern
The original ball and cross were erected by Andrew Niblett, Citizen and Armourer of London, in 1708. They were replaced by a new ball and cross in 1821 designed by the Surveyor to the Fabric, CR Cockerell and executed by R and E Kepp. The ball and cross stand at 23 feet high and weigh approximately 7 tonnes.