Time capsules, those repositories of artifacts concealed for the future, have a long association with Expos. A project in Seattle this year is inviting people to continue a capsule tradition at the Space Needle on the site of World Expo 1962 - Seattle’s Century 21 Exposition.

Taking the W spot on the Expo Architects list is André Waterkeyn, a Belgian metallurgical engineer turned architect who teamed up with his brothers-in-law André and Jean Polak to design the centrepiece of World Expo 1958 Brussels: the Atomium.

Venezuelan architect and activist José “Fruto” Vivas occupies the V spot in the A to Z series. Already celebrated in his home country for his bold creations such as the Club Táchira, Vivas was selected to design Venezuela’s Pavilion at World Expo 2000 Hannover.

Austrian-Australian architect, illustrator and set designer Joseph Urban takes the ‘U’ position of Expo Architects for his contribution to World Expo 1933 Chicago. Already known around the world for his vivid creations – including Austria’s pavilion at Expo 1904 St. Louis - Urban created Expo 1933’s dazzling exterior colour scheme and devised its lighting strategy, an essential aspect of the Art Deco style that was the hallmark of the event.

Kenzō Tange, one of Japan’s leading architects of the 20th century, occupies the T position in the A to Z of Expo Architects. Known for combining Japanese traditions and Western influences in his celebrated urban projects, the Pritzker laureate was the main planner for World Expo 1970 Osaka and designed the Expo’s mammoth Festival Plaza.