An hourglass is a timekeeping device that consists of two glass bulbs connected by a narrow neck. The upper bulb is filled with sand that flows through the neck into the lower bulb, measuring a specific amount of time. When the hourglass is turned upside down, the sand begins to flow, marking the passage of time as it moves from one bulb to the other. It is often used as a symbol of time running out or the fleeting nature of existence. ⌛️