Maastricht, The Netherlands --In this small Dutch town near the Belgian border, a space the size of five football fields brims this week with $4 billion worth of art. There's a $15 million Botticelli, "Madonna and Child with the Infant Saint John," hanging on one wall, and a $7.5 million Gilbert Stuart portrait of George Washington on another.

Art dealers are competing to set up the most opulent booths: One Belgian art dealer has smothered a few walls of his booth with dirt to evoke an eighth-century Korean library. The European Fine Art Fair, or Tefaf, opening Friday, is the sale of the season.