The Rinella Battery in Malta is home to the largest black powder cannon in the world.
This muzzle loading gun was made to fire out to 8 miles (12.8 km) after then recent advancements in ship design. It fired 17.7 caliber rounds (~45 cm) that weighed 2000 pounds (900 kg).
Video: https://youtu.be/aKmi0PN7LxM?si=lZjs7Kww4St6PVlA
Firing:
Apparently only two of these remain.The second one is at Gibraltar.