Baroque architecture is a building style that flourished in Europe between the late 16th and mid-18th century. It evolved out of Renaissance architecture in Italy, when the Renaissance architects began to get bored of the symmetry (对称) and same old forms they had been using for the past 200 years, and started to make bold, curving and not at all symmetrical buildings called the Baroque buildings. Baroque-style buildings share some common characteristics. Marble, gilt (镀金) and bronze were the materials the Baroque architects used in abundance. Oval was the most distinct and a very common shape incorporated into Baroque architecture. Dramatic use of light is important, and is achieved either through strong light-and-shade contrasts or uniform lighting by means of windows. Opulent use of color and ornaments is prevalent, as can be seen in the large-scale frescoes (湿壁画) painted on the ceilings. There is usually a central projection that is quite large and juts outward, and domes erected in a pear shape are often seen. The most well-known Baroque buildings include the St. Paul's Cathedral in the UK and the Palace of Versailles in France. Gian Lorenzo Bernini and Francesco Borromini were the two main architects of the Baroque era.