Plovdiv 40,000 objects. The Museum of Natural Science was inaugurated in 1955 in the old edifice of the Plovdiv Municipality built in 1880. It is among the most important museums in the country with rich collections in its Paleontology, Mineralogy, and Botanic sections. There are several rooms for wildlife and it contains Bulgaria's largest freshwater aquarium with 40 fish species. It has a collection of minerals from the Rhodope mountains. The Museum of Aviation was established on 21 September 1991 on the territory of the Krumovo airbase to the southeast of the city. The museum possesses 59 aircraft and indoor and
History of Plovdiv and the Day of Plovdiv. After Unification Plovdiv remained the second city in population and significance after the capital Sofia. The first railway in the city was built in 1874 and after 1888 it was linked with Sofia. In 1892 Plovdiv became host of the First Bulgarian Fair with international participation which was succeeded by the International Fair Plovdiv. After the liberation the first brewery was inaugurated in the city. In the beginning of the 20th century Plovdiv grew as a significant industrial and commercial center with well-developed light and food industry. German, French and Belgian capital was invested in