This is really amazing and delightful! I had not idea such things were happening around the world! - Jake

Davy writes:

Every year, on the second Sunday of September, the “Stichting Bloemencorso Valkenswaard” (Foundation Flower parade Valkenswaard) organizes the annual Flower Parade. This parade consists of 14 wonderful floats covered with dahlias.  
These large floats are 12 meters long, by 4,5 meters wide, by 6 meters high (= 40 feet x 16 feet x 20 feet). Together with several music bands, the floats make up a feast for the eyes and ears within the streets of Valkenswaard, performed in front of more than 30.000 spectators.  The yearly revised theme of the Flower parade is being acted out by the wagons and all the acts around them, in a combination of street show and music theater. 

The flower floats are being built by people of all ages in 14 neighborhoods of Valkenswaard.  By the middle of June large flower parade tents arise in the village where the floats are being built, and where everyone can give support. Several hundred people are working on the wagons and on the cultivation of the dahlia’s. In the last 3 days before the parade the dahlia’s will be assembled into the wagons, in total 2,5 million flowers, which will be affixed to the wagons with nails.