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
Trolleybuses in Plovdiv the operator is a private company, the city lost the opportunity to acquire 65 mln lv EU funding for purchasing approximately 100 brand-new trolleybuses.The system was officially closed on 1 October 2012 although some trolleybuses continued operation for a few more weeks.Currently there is no trolleybus movement and the municipality has issued an order for dismantling the overhead network. The sole Plovdiv trolleybus line was: , the Plovdiv trolleybus fleet had 47 trolleybuses: Trolleybuses in Plovdiv The Plovdiv trolleybus system () was a part of the public transport network of the city and municipality of Plovdiv, the second most populous