Molasses Wave
Under normal circumstances, molasses is simply a useful ingredient for adding a bit of sweetness to whatever you are cooking. That distinct sweetness is the reason why molasses is a key component in the baked beans that the city of Boston is so well-known for. However, as some Bostonians found out over a century ago, there are rare cases in which molasses can be deadly.

This disaster, dubbed the molasses flood, began when a large tank of molasses suddenly burst open, allowing its contents to spread through the Boston streets. Although molasses is viscous and has a reputation for being slow, this molasses wave moved at an astounding 35 miles per hour. Sadly, it also killed at least 21 people and injured many more.