The duo head to the outback, where they help farmers muster their cattle.

The final leg of their journey takes them to the gateway of the Great Barrier Reef.

The first episode is the Netherlands, where they try out the sport of canal jumping, before the pair don Lycra for a spot of velodrome track cycling alongside a world champion, and take on the world's tallest freestanding climbing wall.

Bradley and Barney continue their European adventure in Germany. They head to the city of Frankfurt, where Brad is pushed to the edge, literally, as he attempts to abseil down the side of a building, facing forwards. The boys also make a stop at a bratwurst-themed hotel and soak up some local Bavarian culture when they have a go at finger wrestling. The pair finish off their time in Germany with a wet and wild adventure in the mountains.

Bradley and Barney arrive in Brisbane, where they swap the RV for electric scooters to explore the city.

The boys have hit the Gold Coast, where Barney has sun, sea and some serious action planned - including setting his old man on fire in an epic stunt.

Actor Bradley Walsh and his 20-year-old son Barney hit the road together, travelling more than 2,000 miles from Los Angeles to New Orleans. In the second leg of their journey, the pair leave the city of Los Angeles behind and make their way down the famous Route 66 to the southwestern state of Arizona. Here, they ride through a deserted ghost town, before the father and son reach Lake Havasu City, where Barney has arranged for them to try jet-skiing. Finally, they attend a Cowboy College, where they learn to become real-life horsemen.

The duo continue their European adventure in Italy, starting in the picturesque Lake Garda, where Barney surprises his dad by explaining they'll be running off the top of Monte Baldo and paragliding over the lake below. The next day Bradley is treated to a hair-raising ride in a Formula 1 speed boat, before the Walshes are invited to the home of opera superstar Andrea Bocelli.

Bradley and Barney’s time in Costa Rica continues and, inspired by childhood memories, the pair head to the country’s cloud forest, where they attempt tree climbing, but this one is slightly taller than your average at 132ft tall. As avid dog lovers, the pair visit a local sanctuary that is home to 2000 free roaming dogs. Bradley and Barney then head into the countryside to meet a former Olympian in Kayak Slalom, and father and son go head-to-head in a time trial. The boys end their time in Costa Rica with a visit to a local celebrity who found fame when he befriended a crocodile.

The actor and his son continue their European adventure in Switzerland, where they take a ride on a mountain rollercoaster before exercising their vocal chords when they try the Swiss tradition of yodelling. The following day, Barney arranges a unique way for them to enjoy some local cheese, and then drive to the Contra Dam, where Barney reveals they are about to attempt one of James Bond's most famous stunts.

Bradley and Barney arrive in Ohio, where they head for Dayton - the birthplace of aviation - before the pair attend a local rodeo later that evening. Brad soon realises that they are not just there to spectate on the sport, they are also expected to take part. However, a nasty fall from an angry bull means Brad spends the rest of the night in hospital.

On the final leg of their journey, the pair continue through the snow to New Hampshire. Here, they meet rally-driving champion Tim O'Neil who gives them a crash course in driving in the ice and snow before they take on an intense time trial. The pair travel on to Maine, where they take part in some wilderness training, before bidding farewell to the RV and heading out into the extremely choppy seas for some lobster fishing. Before heading home, the pair look back on some of their favourite moments from the trip.

The Walshes reach Osaka as they explore the city in go-karts, learn how to become ninjas, and have a go at the quirky yet growing Japanese sport of pillow fighting.

The Walshes are still in Mexico and still on the side of a mountain. Can they complete the final part of the challenge, which requires Bradley to swing across the top of the mountain with nothing but a terrifying drop below him? Once recovered, the father and son head toward Mexico's coast, where Barney takes his dad inside a pitch-black cave that's home to snakes and thousands of bats. They also have fun at a waterpark before joining the cast of Cirque du Soleil

The boys are in Thailand's capital city of Bangkok as they train with a Muay Thai legend and Barney arranges a massage that ends up being anything but relaxing.

The boys arrive in Denmark for the Scandinavian leg of their tour. Bradley's fear of heights is pushed to the limit with a visit to an offshore wind turbine.

The actor and his son head to Hungary, where they take to the open waters of Lake Balaton for a spot of high-speed catamaran sailing with an Olympic crew, before warming up in their RV with some goulash. The pair finish in the capital Budapest, where Barney has arranged to meet a world-famous escapologist.

The Walshes reach Guatemala and pick up their new mode of transport, which quickly becomes a nightmare for Bradley to drive. They travel into the jungle, where they abseil down a lift face into a water fall and meet a quirky shaman who believes in the healing powers of chocolate. They then head off for a bike ride - but what Barney forgets to mention to his dad is that they are riding on a tightrope 25 metres in the air.

The pair continue their European adventure in Poland, going sightseeing in Krakow before attending an exclusive performance by the Polish National Radio Symphony Orchestra in honour of Poland's most famous composer Chopin.

The boys kick off their trip in Japan's capital of Tokyo as they try the national sport of sumo and Brad's fear of heights is put to the test on a hanging bridge.

The actor and his son Barney arrive in Texas, where they enjoy driving around in tanks, experience space travel in a centrifuge and hear campfire tales about UFOs. First up, the pair undertake some centrifuge training, which is used to prepare astronauts for the crushing gravitational forces produced at take-off from the extreme exhilaration. They also head to the outskirts of Houston to meet some UFO enthusiasts who investigate claimed sightings of extra-terrestrials and are gripped by stories of spaceships blocking roads and people being taken by aliens for experiments.

The boys land in the warmer climes of Thailand for the next leg of their trip as they appreciate the stunning scenery from 1000 feet in the air on a motor-paraglide.

In episode four, Bradley and Barney travel to New Orleans in Louisiana, the fourth and final US State of their trip. Sitting on the mighty Mississippi, New Orleans is known for its vibrant nightlife, live music and laidback attitude. Bradley and Barney drive across the border in their RV and head straight for the city’s most famous mode of transport – the steamboat.

Bradley and Barney’s time in Japan continues as the boys get a taste of drifting and Zen meditation, and Brad is pushed to the edge, literally, when he attempts a bungee jump.