On April 19, a convoy of Canadian officials intercepted Joshua Adams, a 24-year-old counselor for homeless gay teenagers in Toronto, on a remote road in central Afghanistan. They tracked him down by following his Instagram account, where he had been posting images of himself drinking tea with the Taliban in Helmand.

Mr. Adams hadn’t traveled the 6,755 miles to Helmand to join the Taliban or to volunteer in a battle against the Islamic State. He had gone to explore the history of Afghanistan, from the empty niches of the Bamiyan Buddhas to the Great Mosque of Herat, famed for its exquisite tile mosaics — monuments attesting to the country’s place on the Silk Road.

Tourist arrivals in Afghanistan have been in steady decline ever since the bulk of NATO forces pulled out of the country in 2014. Muqim Jamshady, who runs Afghan Logistics and Tours, a travel company in Kabul, told me that more than 100 tourists used his services in 2013. That number dropped to a mere 50 tourists in 2017. In 2016, the Wild Frontiers, a British adventure travel company, canceled its “Afghan Explorer” tours because of Afghanistan’s weak security.