Vincennes is a commune in the Val-de-Marne department in the eastern suburbs of Paris, France. It is located 6.7km from the centre of Paris. It is one of the most densely populated municipalities in Europe.HistoryThe Marquis de Sade was imprisoned in Vincennes fortress in 1777, where he remained until February 1784 although he escaped for a little over a month in 1778. Thereafter Vincennes fortress was closed and de Sade transferred to the Bastille.In 1821, the noted French poet, Alfred de Vigny, wrote his poem, "La Prison," which details the last days of the Man in the Iron Mask at Vincennes.A test was conducted in 1849 on Claude-Étienne Minié's invention the Minié ball which would prove successful and years later be adopted by the French army.In 1929, the commune of Vincennes lost about half of its territory when the city of Paris annexed the Bois de Vincennes, a large part of which belonged to the commune of Vincennes.Vincennes was also the site of some famous European colonial expositions in the 20th century in which fairs were held to showcase artifacts from former European colonies.SightsThe city is famous for its castle, the Château de Vincennes, and its park, the Bois de Vincennes hosting the only larger zoo in Paris, Paris Zoological Park (though these two are now within the limits of the City of Paris). It also features a large military fort, now housing various army services. This fort and an adjoining plain known as the "Polygon" has historically been an important proving ground for French armaments.