At sunrise serious ballooners in the northern Croatian town of Prelog are already preparing for the race ahead.

The event is in its fourth year, located on a small airfield about 10 miles south of the Hungarian border.

The event – the first of its kind in Croatia – is growing in popularity and it's one of the town’s main attractions which annually marks the end of summer.

This year also marks Croatia’s hot air balloon open championship, attracting crews from 30 countries from around the world.

They're keen to not only showcase their skills but also popularize the history and engineering associated with this oldest form of airborne travel with a replica of the first balloon, piloted by the Montgolfier brothers in France in the late 1700s.

"Ballooning is the safest form of aviation. It’s the oldest, in 1783 was the first flight. They are incredibly well engineered, they might look like bags of hot air, but there’s a big structure to them. And provided they are maintained and looked after, through maintenance and organization, you won’t have any issues at all. The main cost of flight are your cost of vehicles, equipment, crew, and then the gas you use," says professional ballooner Jonathan Greatrix, a commercial pilot from the UK and a lifelong ballooner.

Starting out as a fixed wing pilot, Greatrix transitioned into balloons, and flew them all over the world, including many places around Europe, and says northern Croatia offers a unique landscape which makes it especially beautiful to glide above.

"Croatia is up there. My first two equals are UK and Croatia, compared to all the countries I’ve flown in Europe. Yeah, it’s beautiful. What I love about it is all this expanse of water. So, we’ve got mountains over there, hills, we’ve got forests, we’ve got the water. It’s a lot. It’s very, very, beautiful," says Greatrix.

The event is organized by the Zagreb Balloon Club, the country’s biggest and oldest ballooning association, which formed 40 years ago.

It was the first balloon club established in the former Yugoslavia.

It's now run by the founder’s son, Igor Miklousic.

It now has some 200 full-time members, including about a dozen who represent Croatia in international competitions.

Miklousic said that this year’s Prelog festival takes place shortly after the European championships in nearby Austria and before the world championships scheduled for September in Poland.

It now attracts competitive crews.

AP video shot by Sasa Kavic

Production: David Spaic Kovacic