Whether they travel by land, sea, or air, a growing number of tourists are taking holidays which take them to a wide variety of destinations.
However, whilst it is not unusual for holidaymakers to visit a handful of countries during their trip, one unconventional railway journey can take passengers through 13 different countries.
Despite not being a direct line, ambitious tourists wanting to experience the best of Europe and Asia can take a wide vairety of train journeys that span more than 11,600 miles.
Those wishing to take the journey will need to leave themselves plenty of time, with the route typically taking around 21 days, without considering any breaks tourists may wish to take or flights home.
Nevertheless, the ultimate railway journey is not as expensive as tourists may think, with passengers charged $1,350 (£1,065), whilst also being significantly better for the environment.
The world’s longest possible train journey begins in the city of Lagos, the largest city in the western Algarve in Portugal. Before getting on board, visitors can relax on one of the many beaches, take in the unique Ponta da Piedade rock formations, or simply have a stroll along the narrow streets of the old town.
Once on the train, passengers will soon arrive in the Portugese capital of Lisbon, before changing for the small French commune of Hendaye in the Basque Country, and Paris.
One of the more challenging stretches of the journey at the moment is the 40-hour ride from Paris into Moscow, which could be difficult to visit due to the current conflict between Russia and Ukraine.
Having arrived in Moscow, passengers would change once again to a line heading for Beijing, the capital of China on the Trans-Siberian railway. This stretch of the journey can take up to six days alone, giving passengers enough time to admire the views from their carriage.
Once tourists have reached China, they will then need to take another train heading to Laos, in which they will pass the mountains of Kunming, before changing once again to head to Bangkok, the capital of Thailand.
After making one final change at Padang Besar, a small town on the border between Thailand and Malaysia, passengers will finally arrive in the city-state of Singapore, where their journey will come to an end.
Since the train journey is made up of several smaller routes, passengers are able to cut down some stretches of the journey they do not have the time to make, and can easily spend as much time as they would like in certain destinations.
Given the complexity of the journey, in addition to the current political situation in Russia, tourists hoping to make this trip will need to book it themselves, and could risk delays and disputes causing significant problems.
However, those with the time, funds, and nerve to make the longest train journey would have plenty of positive memories and staggering photos from their time away.