Aalsmeer Flower Auction (Bloemenveiling Aalsmeer) is a flower auction that takes place in Aalsmeer, Netherlands. It is the largest flower auction in the world. The Aalsmeer Flower Auction building is the fourth largest building by footprint in the world, covering 518,000 square metres (5,580,000 sq ft; 128 acres). 

Flowers from all over the world – Europe, Ecuador, Colombia, Ethiopia, Kenya, and other countries—are traded every day in this gigantic building. Around 20 million flowers are sold daily. This increases by around 15 percent around special days such as Valentine's Day and Mother's Day. 

 Their flowers are subjected to around 30 quality checks so that they can be graded on a scale (A1, A2 and B).

The auction is set up as a Dutch auction in which the price starts high and works its way down. Bidders get only a few seconds to bid on the flowers before they are sold and passed on to the new owner. 

According to en.wikipedia