A forge is the workplace of a blacksmith. Forging is the term for shaping metal into tools, horseshoes or other useful objects.
Usually, blacksmiths heat the metal to high temperatures, until it is red or orange, before forging it. When the metal is hot, it is easier to shape and less likely to break.
A basic forge has a hearth for heating the metal to a temperature that makes it flexible; an anvil to lay the metal pieces on while hammering; and a slack tub, which is a container full of water, to rapidly cool and harden forged metal.
Tools used by blacksmiths in forges include tongs to hold the hot metal and hammers to strike it into shape.