throughout its existence of more than 150 years, the expo will bring new knowledge from a specific period of time and trend of development, reflecting the human civilization. the main attractions of the first session of the world expo in 1851 in the crystal palace in london: almost 500 meters long palace built of cast iron and glass. subsequently, the participating countries will offer similar advantages to introduce from time to time every few years.

　　today expo is the economic and cultural olympiad of the world, a competition among nations, as well as among exhibitors from the private sector on a given subject. at the same time, it is about marketing countries internationally. expositions of the first category last a maximum of 6 months and may be held on an enormous area. but at a time when information as well as goods can be had through the internet and other technologies 你也可以投稿, they remain a place of rendezvous and of authentic experiences.