Topher Richwhite and Bridget Thackwray have battled many dangers but as they approach the third year of their spectacular journey the length and width of the world, coronavirus is becoming the biggest roadblock.
The pair started their 350,000km road trip - which they labelled Expedition Earth - in their trusty Jeep, Gunther, in April 2018 and have been to 67 countries. They have just started their 3rd and final leg, which will see them drive home through Asia.
The ETA at the finish line in Auckland was set for December this year but they are unsure they will make it because of coronavirus delays.
Richwhite, from Auckland, and Thackwray, from Kerikeri, are on the Yamal Peninsula in northwest Siberia, after finishing one of the most extreme journeys into one of the world's most remote regions. Yamal means "end of the land".
They had planned to drive southwest through Moscow over the next three months before visiting Georgia, Azerbaijan, Iran. Their journey would then take them north through Turkmenistan, Uzbekistan, Tajikistan, Kyrgyzstan, Kazakhstan, Mongolia and south again through China and India.
The first potential roadblock is getting off the peninsula. There is only a small window during the year when rivers freeze into 2m ice sheets and can be driven over and the area can be accessed. The couple are worried that if the river thaws, the Jeep will be stuck in the area until next winter.
If they do manage to get off the Yamal Peninsula, border restrictions, which have been increased in China - the centre of the coronavirus outbreak - and in bordering countries, including Mongolia and Iran may stop them driving through those countries.
"We were anticipating the only challenges for leg three to be the political instability in Iran and a few Taliban hot spots around the borders of Afghanistan and Pakistan," the couple tell Spy.
"We have been speaking to the NZ Embassy in Moscow and will make a call if we fly home when we get there, but we are currently trapped in arctic Siberia. Our only route south is a frozen river that snowed over last week. If the river thaws, Gunther will be stuck here until next winter."
Coronavirus also means a globally-televised series due to be filmed by BBC Studios is unlikely to go ahead. The studio was due to join the couple on the final leg of their journey.
They have also been approached to work with Rolex's Perpetual Planet programme.
In Siberia, their faces are wind burnt as they have been digging Gunther out of the snow in high winds and temperatures of -20C.
"If we do have an emergency, we are prepared. We carry our own blood-test kits and carry a Garmin SOS device that will call in a rescue team if we need extraction. We're also covered by insurance, which gives us a lot of comfort that we'll be looked after in almost every country along the route."
The couple - on a round-the-world mission to highlight the impact of a growing human population on the environment - is used to challenges.
Last year, they drove through Mozambique just after Cyclone Idai, when there was a huge outbreak of cholera, an infectious disease that causes diarrhoea and dehydration. With extra planning and preparation for such situations, they were able to get through.
Other dangers have included being amid civil unrest in Nicaragua. In Ethiopia, six teenagers with AK47s pulled them over, held them at gunpoint and ransacked their belongings before letting them go. They were also nearby during the massacre in Khartoum, in Sudan, on June 3, where more than 100 pro-democracy protesters were killed by paramilitaries.
"In one area of Ethiopia our escort pulled a knife on our security and in another area we were stopped by gunmen and Topher was pulled from Gunther," says Thackwray.
"Although Sudan ended up being more terrifying as we were in the country during the massacre and later found out we had been camping next to where the paramilitaries were training, the same group responsible for throwing the people into the Nile alive, with bricks tied to their feet, "
It was reported the paramilitaries threw dozens of bodies into the Nile to hide the number of casualties.
Last year Richwhite and Thackwray carried out a number of assignments for National Geographic, such as filming the impact human disease can have on gorillas. Their footage is being used throughout the National Geographic platforms.
During their time in Africa, the couple also worked with a number of smaller conservation groups.
"Overall, our findings are that every environmental issue points to one common denominator; overpopulation."