From the moment this fair opened its doors in 1988, at the MECC in Maastricht, TEFAF has been dedicated to presenting the world’s finest art—across categories—under one roof. What began as a radical idea for a new fair model has transformed into “the greatest fair in the world,” according to one of TEFAF’s first exhibitors, the Old Master dealer Johnny van Haeften. The fair’s 38th edition features 273 prestigious dealers from 21 countries. Modern and contemporary art, photography, jewelry, 20th-century design, and works on paper are among the offerings. Don’t miss the curator course, which debuted last year and is aimed at “emerging” collectors. Among the prize pieces at the fair? Picasso’s Les Dormeurs. Andy Warhol’s Grace Kelly. And Margot McKinney’s Atoll Collier, a necklace with 13 rare boulder opals. —Elena Clavarino