It happened on the same day, when German battleship, Bismarck sunk Hood, the pride of the British fleet at coasts of Greenland. On May 24th, 1941, the Royal Hungarian 1./3. TF flying squadron conducted aerial photography over the recently occupied Serbian capital, Beograd. With these pictures the Hungarian High Command wanted to refresh the outdated sections of the Third Military Survey (made before 1914.) The photographed area overstreched the current borders of Hungary, they flew over Serbia, western Romania and Southern Transylvania. It was very likely that these countries were forgotten to inform about this action.
This is how the Serbian capital looked like from a bird’s eye view on may 24th, 1941. According to the shadows on this picture we can tell that the photos was taken early in the morning, from which the cartographers later joined this 6065/3 section. We still see traces of war, even from this height. The middle of the railway bridge, overarching the Danube towards the Banat is missing. The bridge I. Alexander leading to Zemun is also disappeared, probably sunken in the Sava river.
|Fig. 1. Section 6065/3 Beograd. Archives of the Hungarian Military Museum|
If we examine the hydrologic aspects of Beograd’s surroundings, we may miss something. The Great War Island (Hungarian: Nagy Hadi-sziget, German: Groß Kriegs Insel, Serbian: Велико Ратно Острво) at the Danube and Sava confluence is nowhere to be found. Once the greatest island just under the walls of Beograd has disappeared. This island played an important and strategic role in every siege of Nándorfehérvár, and later Beograd. It belonged to Zemun, before 1918, and stood right next to the old Hungarian-Serbian border, which was the middle line of the Sava river.
|Fig. 2. There is no trace of the Great War Island|
Year 1941 was extremely wet in the Carpathian Basin. Because of the thick snow and heavy rains ice flood on the Danube devastated the surroundings of Kalocsa in February. Three months later, in May the spring floods on the Tisza river caused high water at Beograd. That time the full length of the Tisza river was within the borders of Hungary. The Hungarian authorities were on call for 210 days on the dikes of the Tisza river, out of this time 144 days were critical. There were times when flood threatened on 80% of the Tisza river's full length. This flood raised the level of the Danube from the Tisza confluence at Titel.
We see the consequences of the Tisza river flood on the aerial photo. The Danube fills utterly its floodplains between the dikes. But where have the Great War Island disappeared? Only the Danube is visible between Zemun and Beograd. If we take a look at the two islands (Cervenka and Kozara) on the left banks we see the riverine forests are also completely flooded, only the top of the trees reach out from the water. If we suppose that this time there were zero trees on the Great War Island, it is possible that the whole island was flooded by the Danube. Otherwise we should see 2 square kilometers of trees standing in the water - just like on the below 19th century painting – in front of the Beograd fortress.
|Fig. 3. An oversight on Beograd from Zemun with the Great War Island /source: politikin-zabavnik.rs/|
Supposing the Hungarian cartographers did not retouched the island from the pictures (it would not make any sense) we have to look for the answer somewhere else. Between the two world wars, the Yugoslav capital develoment completed plans for filling up the Sava marshland up to the city of Zemun. The sparwling new town could not have been built on a floodplain, which is often flooded by the Sava and the Danube, or both together. It is possible that the Great War Island was simply dredged in the '30s to fill these floodplains?
|Fig 4. Beograd in 1937, picture taken from the southwest /soruce: falanszter.blog.hu/|
If we take a glimpse from a bird's eye view on Beograd in 1937, there is the Great War Island beyond the newly erected Market town. This is a definetly plain island, but except for two solemn trees there is no forest on it. Where have the trees been disappeared? If we suppose that the vegetation was destroyed in the first world war, there was 23 years for the trees to grow back on this uninhabited island. Have the trees been cut because of a recent construction area? It is also not very much likely, because building houses on a floodplain was not a good idea back then, when a moderate flood covered the whole ground. The most obvious and down to earth explanation for the disappearance is there used to be the gardens and pastures of Beograd between the two world war. In this case it was not a surprise when the 1941 Tisza river flood has hidden the Great War Island island from the cartographers camera.