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
Plovdiv Airport and Frankfurt) in 2015 after two years of stable operation. The government have started the first concession procedure back in 2011, but there were no candidates for it. The second attempt for the concession was made in the spring of 2016 when the government have opened a tender for a 35 years concession of the airport, but the tender was shortly cancelled for non-compliance with European rules. In December 2016 the government opened the 3-rd tender for the concession. In the new procedure 3 companies have made the bid for the airport - Silk Road Plovdiv Airport, Consortium Plovdiv Airport