ExpoBids is a project of ExpoMuseum.com and tracks the various bids for the BIE-recognized expo (or world's fair in US parlance) to be held in 2017 and the BIE-sanctioned expo to be held in 2020. We also track the possible bids for Expo 2022 or Expo 2023.
Expo 2020 is the larger of the two, analogous to the Summer Olympics. It is considered "sanctioned" by the BIE. There are no size limitations for sanctioned world's fairs and many nations build their own stand-alone pavilions. They're held every five years. Hannover, Germany hosted Expo 2000; Aichi Prefecture, Japan hosted Expo 2005; Shanghai, China is hosting Expo 2010; and Miltan, Italy is preparing to host Expo 2015. Themes for these pavilions are fairly broad and typically have several smaller sub-themes. Expo 2025 will also be of this size.
Expo 2017 will be the more modestly sized world's fair of the two. It can be thought of as analogous to the Winter Olympics. It is considered "recognized" by the BIE, meaning that it has a limited site size and national pavilions are usually exhibited in a modular system provided by the expo authorities. They can be held 2 or 3 years after a "sanctioned" expo. Zaragoza, Spain hosted Expo 2008 and Yeosu, South Korea will host Expo 2012. It is meant mostly for smaller cities or for cities in less developed nations. Themes for this size exposition are more limited, as well. Expo 2022 or Expo 2023 will follow this model.