EXPOs are divided by the B.I.E. into different categories.
Today, under the auspices of the B.I.E., world exhibitions are held mainly in 4 EXPO categories organized:
- World's Fairs
- Specialised Expos
- Horticultural Expos
- Triennale di Milano
The so-called World EXPOs are designated by the B.I.E. as "International Registered Exhibitions".
They last six months
There are also "Specialised Expos". Under this designation fall the smaller world exhibitions, formerly called "International Recognised Exhibitions (2008 to the present)," International Specialised Exhibitions" (1981-1998) and "Special Exhibitions" (1936-1975).
These usually last three months.
More information about the different categories, EXPO formats and designations can be found here: