In the medieval times, technology as we know it did not exist, but that didn't stop people from building impressive structures and creating ingenious tools. They used what we now call 'simple machines' to make their work easier. These simple machines include the lever, the wheel and axle, the pulley, the inclined plane, the wedge, and the screw. These machines were common in many medieval professions. Blacksmiths used levers to operate their bellows, which stoked the fires of their forges. Millers used wheels and axles to convert the flow of water into energy to grind grains. Builders used pulleys to lift heavy stones for construction. These simple machines work based on fundamental principles of physics. For example, a lever allows you to lift a heavy object with less force by increasing the distance over which you apply your effort. While we now have advanced technology, these simple machines still show up in our everyday lives. They remind us of the cleverness of our ancestors, who used their understanding of the world to make their lives easier.