The Minnesota State Capitol dome is actually a three-dome structure. The exterior one you can see from the outside, the interior one you can see in the Rotunda, and an unseen middle dome that keeps frost and water from damaging the interior dome.
During the past few years workers have repaired the exterior dome to prevent water damage and installed a ventilation system to move the humidity out of the dome. New flashing for drainage was also installed around the base of the middle dome to trap and remove water permeating from the exterior dome. The finial (the golden ball at the top of the exterior dome) was repaired and new gold leaf applied, new windows were installed and the dome’s chandelier was cleaned and restored. But there is still another $260 million worth of repairs to be done to get Minnesota’s Capitol back into the shape it was when it opened in 1903.