Passengers travel on the London train and underground system during the Christmas party season, December 18, 2015. (Photo by Paul Hackett/Reuters)

Travellers wait in queue to test for COVID-19 at a train station in Mumbai, India, Tuesday, November 30, 2021. (Photo by Rafiq Maqbool/AP Photo)

The performers prepare for the show. Fontana, a travelling water circus produced by Cirque Du Liban at Festival City in Dubai. (Photo by Chris Whiteoak/The National)

Indian Muslim devotees travel in an auto rickshaw during the Urs festival in Ajmer, India, Thursday, April 23, 2015. Thousands of devotees from different parts of India travel to the shrine of Sufi saint Khwaja Moinuddin Chisht for the annual festival marking the saint's death anniversary. (Photo by Deepak Sharma/AP Photo)

Pod of dolphins surf effortlessly through the waves in the wild traveling at speeds up to 20 mph. (Photo by Greg Huglin)

People ride a bus as they travel in Yangon, Myanmar January 14, 2017. Picture taken January 14, 2017. (Photo by Soe Zeya Tun/Reuters)

People use a board to travel on a flooded street after heavy rainfall in Baghdad, Iraq, October 31 2015. (Photo by Ahmed Saad/Reuters)

South Asian countries in terms of total contribution of travel and tourism to GDP. #6. Vietnam, Total GDP: USD 202.6 billion (2016). Contribution of Travel and Tourism to GDP: 9.1% . Here: A boat in the Thu Bon River, Hoi An, Vietnam. (Photo by Domingo Leiva/Getty Images)