Petrópolis, also known as The Imperial City of Brazil, is a town in the state of Rio de Janeiro, about 60 km from the state's capital and altitude: 830 meters (2750 feet) above sea level.

Nested among the forested hills of the Serra dos Órgãos ("Organ Hills"), in the valley of the Quitandinha and Piabanha rivers, Petrópolis is a popular summer holiday spot. Besides the climate and surroundings, the main attraction is the former Summer Palace of the Brazilian Emperors, which is now a Museum, specializing in Imperial history and memorabilia.

The town's name ("city of Peter") honors Emperor Pedro I, the nation's first monarch. The city was the summer residence of the Brazilian Emperors and aristocrats in the 19th century, and was the official capital of the State of Rio de Janeiro between 1894 and 1903.

The town's origins can be traced to a certain Bernardo Soares de Proença , who in 1720 opened an alternative route between Rio de Janeiro and Minas Gerais, across the Serra da Estrela. While traveling to Minas Gerais along this route, Emperor Peter I found the region's climate pleasant, so in 1830 he bought a farm, and had his Summer Palace built there. Other Brazilian aristocrats eventually followed suit.

Under his successor Pedro II, German farmers from the Rhineland were encouraged to immigrate and to settle on the Emperor's outlying lands, to help give the Palace a charming urban setting. The settlement of Petrópolis was founded on March 16, 1843, being promoted to district in 1844 and finally city in 1857. The road connecting the city to Rio de Janeiro was opened in 1910 and paved in 1928.

The Imperial Museum, former Summer Palace of the Imperial Family

On a visit at the Philadelphia Exposition of 1876, Pedro II was impressed by Alexander Graham Bell's new telephone, and had a line installed between the Summer Palace and the farm headquarters.

Even after the establishment of the Republic and the exile of the Imperial family in 1889, the Summer Palace continued to play a significant role in Brazilian history. In 1903 it saw the signing of a peace treaty with Bolivia, which gave Brazil the Acre territory. In August 15, 1947, the Organization of American States opened there the Conference for the Maintenance of Peace and Security in the Continent, from which derived the Interamerican Treaty for Reciprocal Assistance.

Stefan Zweig and his wife spend their final year in Petropolis before committing suicide in 1942.