On October 11th I was in Monte Lessini, hilly landscape north of Verona, Italia. There is a huge natural bridge, rising 29 meters off the valley floor, spanning nearly 50 meters and being 6 meters wide. So it is obviously bigger than Prebischtor (Pravcicka Brana).
Natural Bridge Kentucky is quite imposing spanning 78 feet. The center of the arch is 68 feet high and the pavement 40 feet above that. Material: Sandstone. Position: Skyline. The on ramps make it much more than 78 feet in length. This is depicted in the Red River Gorge Page at Summitpost. I think Manning bridge in Kentucky is the longest eastern span at 154 feet.