A combination of pictures shows German Chancellor Angela Merkel and US President Barack Obama try the virtual reality device PMD during the opening day of the Hannover Fair in Hanover, Germany, April 25, 2016. [Photo/IC]

The 2016 Hanover industrial trade fair opened in Hanover, Germany, on Monday. The world's leading fair for industrial technology, with about 5,200 exhibitors from 70 nations, runs till April 29 with the US as this year's partner country.

On the opening day, around 20 Chinese and German cities formed an alliance to boost communication and cooperation between the two countries.

Great efforts will be made by both sides to promote common development in modern industry and industrial service sectors of alliance members, according to the Sino-German Industrial City Alliance.

Up to 18 industrial cities including 11 Chinese cities and 7 German ones have joined the alliance.