Solar Impulse 2 became the first solar-powered aircraft to circle the globe when it touched down in Abu Dhabi early Tuesday, the mission's team said. 
The single-seat, solar-powered aeroplane began its journey in Abu Dhabi in March 2015 and stopped in countries including Egypt, India, Spain, China, Australia and the US. 
It was piloted in turns by Bertrand Piccard and Andre Borschberg of Switzerland. Piccard piloted the carbon-fibre plane for the final 48-hour leg from Cairo, reaching Abu Dhabi around 0405 am local time (0005 GMT). 
Previous legs on the plane's world trip have lasted several days as the plane has an average airspeed of 75 kilometres per hour. 
A normal commercial flight between Cairo and Abu Dhabi - a distance of around 2,500 kilometres - takes just under four hours. 
During its round-the-world journey, the plane spent the equivalent of 25 days in the air. 
On June 23, Solar Impulse 2 made history by becoming the first solar-powered aircraft to cross the Atlantic Ocean, flying 70 hours from New York to Seville in Spain.

Source : QNA