The first World Expo took place in Crystal Palace in London's Hyde Park in 1851. But not least a row of World Exhibitions in Paris helped to create a tradition of regular Expo's. Among the most famous was held in 1889 when the Eiffel Tower was build as entrance for the Expo.

There are two kinds of World Expo:

The World Registered Expo and the International Recognized Expo

The large World Expo's are - as a general rule - held every five years. The next registered World Expo will be held in Shanghai 2010 in China. The theme for the Expo in Shanghai will be: "Better city - Better life" and will in many ways have focus on sustainable city development.

The next registered World Expo after Shanghai will be held in Milano (Milan) in Italy in 2015 having the title Feeding the Planet, Energy for Life. It is not yet decided which city will host Expo in 2020, but among others Copenhagen has shown interest.

The International Expo's are unlimited in size and are normally open for half a year. In Shanghai 70 million visitors are expected to see the Exhibition.

The World Expo'92 in Sevilla (Seville) in Spain had 42 million visitors. The present record was the Osaka Expo in Japan in 1970 - visited by 64 million people.

Smaller are the International Recognized Expo's. They are limited to a size of 25 hectares and are normally open no longer than 3 months.

The latest registered World Expo opened at the 14th of June 2008 in Zaragoza in Spain under the title: Water and Sustainable Development. The next recognized Expo will be in 2012 in Yeosu in Korea with the subject "The Living Ocean and Coast - Diversity of Resources and Sustainable Activities".

Since 1928 the World Expo's have been coordinated by BIE - Bureau International des Expositions having more than 150 member states. The organization is located in Paris.