Jaivana Cannon in know as the largest cannon in the World. It was manufactured in 1720 and now it is preserved in Jaigarh Fort, Jaipur, Rajasthan, India.
The cannon was fired only once by loading 100kg of gun powder. It was fired for the distance of 35km. It was just a test fire and this cannon was not at all used for any war.
Now kept in the below location:
https://goo.gl/maps/3rKaLa3P1KUU9pEx5
I visited this location last month. This cannon is about 50 ton weight and looks extremely nice, when you think of how precisely it was manufactured.
If somebody is planning for a trip in Jaipur, then you must visit this place.