With 90 minutes to go before curtain, a group of stagehands rushed to repair a broken door on the set of Verdi’s “Macbeth” at the Grosses Festspielhaus in Salzburg, Austria. In a costume shop next door, workers combed and curled a line of unruly wigs. Lining a plaza outside, men in tuxedos and women in dirndls gathered to sip schnapps and Champagne.

It was a typical August evening at the Salzburg Festival, which every summer becomes the center of the classical music world, cramming more than 200 opera, concert and theater performances — roughly the equivalent of Carnegie Hall’s entire season — into six weeks. It is a mammoth undertaking that involves about 3,500 artists; 1,000 staff members; 16 stages; and a budget of 75 million euros (about $88 million). This summer alone, there were six staged operas and four plays, featuring more than 1,500 costumes, including leopard-print hats and glittering Swarovski-covered masks.

“There’s no room for error,” said Georg Schlager, a stage manager overseeing repairs on the “Macbeth” set, which would be torn down in the wee hours to make room for an orchestral rehearsal the next morning. “We want every detail to be perfect.”

No summer festival is quite like the one in Salzburg, a city of around 150,000 at the foot of the Austrian Alps that was the birthplace of Mozart and the bucolic backdrop for “The Sound of Music.” Here, the offerings are rich and abundant — Mozart symphonies at 10 a.m., vocal recitals at 10 p.m. — drawing more than 256,000 visitors from around the world, including more than 500 journalists.