Hungary, but returned in 1813 and unsuccessfully tried to find the gold which he has dug and hidden somewhere on Ada. Starting in 1821, the state government decided to organize food trade and to check the quantity and quality of the goods imported to the city. The project included introduction of the excise on the goods (in Serbian called trošarina) and setting of a series of excise check points on the roads leading to the city. One of those check points, which all gradually also became known as trošarina, was located next to Topiderka's mouth into the Sava, across the northern tip of Ada. Built in the 1830s and 1840s, it became known as Gospodarska Mehana. It was also a location of the ferry which transported pigs across the Sava into the Austria. This trošarina also functioned as a customs house. On 25 January 1859, when prince Miloš Obrenović and his son Mihailo Obrenović returned to Serbia, they disembarked here. In this period, Ada became a home to ferrymen and numerous smugglers, who operated both ways. THe island was sort of a base where the goods was prepacked either for the customs, or was simply smuggled. The importance of Ada Ciganlija can be traced back to 1821, when it was declared a protected public domain by then Prince of Serbia, Miloš Obrenović. The first official urban plan for Belgrade was drafted in 1867. It was a work of Emilijan Josimović, the first Serbian trained urbanist. He envisioned Ada as the main sports' center of Belgrade and was to be transformed in the "source of fresh air", a term Josimović used for large forests. Neglected since then, Ada came to the spotlight in 1908 when the Society of the Belgrade's journalists organized the first journalists' ball on the lower tip of Ada. In 1911, the first Serbian feature-length motion picture, The Life and Deeds of the Immortal Vožd Karađorđe was filmed on the island. World War I On 28 July 1914, when Austria-Hungary declared war on Serbia, thus triggering the World War I, Serbian forces spread over the island to prevent Austrians to use it as the starting point of entering Serbia. Two major battles ensued, on 22–24 September 1914 and in September 1915. In an effort to exploit the withdrawal of the Serbian army from Syrmia in September 1914, Austro-Hungarian Lieutenant field marshal decided to conduct the feint attack on