You must visit the Lonjsko Polje Nature Park in Croatia and Cigoc, Croatia's famous Stork Village. The time to visit is between May and beginning of August, when the storks are breeding on top of the old oak houses. Indeed, you can sleep in one of these restored antique houses if you wish.
Meanwhile, in the nature park you'll come across Turopolje pigs the whole year, diving for mussels and waternuts in the flooded forests.
The hatching of the Mayflies in the Tisza Rivers is one of the Danube's greatest natural events. Villagers come from miles around to marvel at the "flowers" blooming on the river's surface – millions of long-tailed mayflies. Rising in huge clouds, they take flight, reproduce, and perish, all in just a few hours.
The best places to watch the phenomenon are in Tokaj on an oxbow lake or at the riverside. Or on Bodrog, a tributary to the Tisza.
At Camp Matica in the heart of the Danube, you live on an island in the middle of the Delta, far away from civilisation. You can fish from your personal platform or get guided tours through the gorgeous delta with local rangers.
Contact: Nicolae V. Dudas (Nico), (+4) 0761127396, email@example.com
Just east of Bucharest, you'll find arguably the best carp fishing spot in the world. The biggest carp ever caught was landed here in 2001 (it was a staggering 82lb). Renowned angler, Rob Hughes calls it 'the best lake in the world' and anglers are regularly pulling in carp weighing more than 50lb.
Kopački Rit, is a nature park in eastern Croatia, located north-west of the confluence of the Drava and the Danube, close to the border with Serbia. It comprises many backwaters and ponds, and is close to the Baranja region and its famous Wine Road. Make sure you drop in on Josic, a beautifully located restaurant in the middle of the vineyards, where you can eat as well as enjoy the local wines.
Wild Danube will be broadcast on the Nat Geo Wild channel on 21 April.
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