HANOVER, Germany, April 22 (Xinhua) -- Hanover Fair, the world's leading industrial trade show, opened on Sunday, as German Chancellor Angela Merkel stressed the importance of free trade.

The five-day trade show, under the theme of "Integrated Industry -- Connect and Collaborate", features five parallel shows, namely IAMD (Integrated Automation, Motion and Drives), Digital Factory, Energy, Industrial Supply and Research and Technology.

More than 5,000 exhibitors from 75 countries and regions are expected to participate in, and 60 percent of the exhibitors are from outside Germany. China and this year's fair partner country Mexico come after Germany in terms of the number of exhibitors.

Speaking at the opening of the fair, Merkel said that multilateral cooperation can add value for everyone. "That's why we are promoting global trade that is as free as possible," she said.

Hanover fair started in 1947 to boost the economic recovery of post-war Germany. It has repeated every year ever since and become the show window for the world's leading industrial technologies and equipments.