The Sheldonian Theatre is an iconic ceremonial building in the heart of Oxford, England, designed by Sir Christopher Wren and built between 1664 and 1669 for the University of Oxford. Its primary use is for university ceremonies such as matriculations and graduations, as well as concerts, lectures, and public events.
 
Commissioned by Gilbert Sheldon, then Warden of All Souls and later chancellor, the theatre is considered one of Wren’s earliest architectural masterpieces[wikipedia +1]. The design was inspired by Roman theatres and the structure notably features a large D-shaped auditorium and a stunning eight-sided cupola.
The original roof, innovative for its time, was constructed with trusses held together by iron bolts and plates, creating one of the largest unsupported flat floors of the era.
 
Interesting facts...
The figures outside the Sheldonian Theatre are known as the “Emperor Heads.” There are 17 stone heads depicting bearded men that stand along the front of the theatre. These statues were first commissioned by Sir Christopher Wren in the 1660s when the theatre was built. The current set of heads dates from the 1970s, forming the third generation of these sculptures, as earlier versions suffered from weathering and erosion over time.
The original heads were carved by William Byrd, and it is thought that Wren may have been inspired by similar heads he saw outside a French chateau. Each of these heads weighs about one tonne. Many of the retired heads from previous generations have been lost or given away, with some now found in gardens, Oxford colleges, and other locations around Oxford. A project has been ongoing to track and conserve these heads, including public art installations and exhibitions discussing their history and cultural significance