The Glory Hole

Glassblowing involves three furnaces.

The first, which contains a crucible of molten glass, is simply referred to as "the furnace."

The second, shown here, is called the "Glory Hole," and is used to reheat the piece of glass gathered on the blowpipe in between steps of working on it.

The final furnace is called the "lehr" or "annealer," and is used to slowly cool the glass over a period of a few hours to a few days, depending on the size of the piece. This keeps the glass from cracking due to thermal stress.