Constantine Palace in Strelna is called after Pavel the I's son, but the project has started in Peter the First period. He ordered to construct a palace in Strelna in 1709, and it took eleven years to find the architect and design a project. In 1797, the palace became the property of Duke Constantine, who decided to make changes in the existing facade and interior. However, all efforts went to blazes after a fire in 1803, so Voronikhin and Russka architects had to make another reconstruction, keeping the ancient art style, though.
After the revolution, the cathedral served as a school; after some time, it was turned into a sanatorium. It was ruined almost entirely during World War II. Still, it became one of the most significant sights of Saint Petersburg and its suburbs only after 2003 when it went through major reconstruction and was turned into The National Congress Palace. Today, it holds major international meetings, conferences, and summits, including the G20 in 2013.
You can visit the palace as a tourist and access a limited number of halls: the Blue Hall, Marble Hall with a splendid Finnish Bay view, and Belveder hall, which usually serves for small meetings and press conferences. The exposition section of the palace keeps the original paintings of famous Russian artists, including Repin, Bruyllov, and Serov; besides, there are original household items and furniture from the 18th and 19th centuries.