ISTANBUL — After days of being the target of tear gas and police water cannons, protesters in Gezi Park, in Taksim Square here, were tense on Wednesday night, girded for conflict. Instead they got a piano performance.

Davide Martello, a German musician in the new age, Paul Winter mold, arrived with a three-man team, hauling a grand piano in a trailer. After unloading the instrument and placing it inside the entry to the park, he began to play.

People stopped to listen. The restless crowd began to calm and organize around Mr. Martello. Soon photos and videos of the performance were zinging around the globe, ending up on blogs, online news sites and Facebook pages.