A barrel or cask is a hollow cylindrical
container, traditionally made of wood
and bound with iron
hoops. The term
"barrel" typically refers to wooden vessels that are small enough to
be moved by hand, up to puncheon
size (see below). Someone who makes such (wooden, iron-bound) barrels is known
as a cooper.
Contemporary barrels are also made of aluminium and plastic.
This one obviously was filled with something explodable.