David Hallberg made ballet history in 2011 when he left New York for Moscow to join the top ranks of the Bolshoi Ballet, becoming the first American dancer invited to join the insular Russian ballet company. Traditionally, traffic had gone the other way—and usually at great risk to the dancers involved. (With the KGB in hot pursuit, Mikhail Baryshnikov and Rudolf Nureyev had to defect in order to dance with Western companies.) As something of an ambassador for his art form, Hallberg, a star of American Ballet Theatre, has performed regularly as a guest artist with companies around the world. It’s been part of his mission to learn from the best and introduce new elements into his dancing—not to mention to export a little American know-how to distant corners of the globe. Last Friday, Hallberg presented his latest experiment in cultural cross-pollination. For Legacy, a one-night program at Lincoln Center’s Koch Theater, he brought together dancers from the various companies in which he’s danced. They included the Mariinsky Ballet (formerly the Kirov), the Bolshoi Ballet, the Australian Ballet, the Tokyo Ballet and American Ballet Theatre’s junior Studio Company. Before the curtain rose, Hallberg invited W into the wings for a glimpse of rehearsal—and for that even rarer glimpse of dancers in repose or in transitional moments between preparing and dancing. Take a look as Hallberg provides a guided tour.