The Istanbul Military Museum showcases a fascinating collection of five thousand artifacts, spanning from the Ottoman era up to World War II. Among these historical pieces, one item stands out—a massive chain once used by the Byzantines. This chain was famously stretched across the mouth of the Golden Horn in 1453 to prevent the Sultan's navy from entering during the siege of Constantinople.
In the museum's courtyard, the Janissary Band, or Mehter Takımı, performs each afternoon at 15:00. Recognized as the world’s oldest military band, they play traditional march music while dressed in authentic uniforms. Their concerts bring a unique atmosphere to the museum, blending music and military history for visitors to experience firsthand.
Source - https://en.wikipedia.org/wiki/Istanbul_Military_Museum