Turnstiles are mechanical gates or barriers that allow one person at a time to pass through in a particular direction, usually used for crowd control or access control. They are commonly found in public transport systems, amusement parks, stadiums, and other crowded venues. Turnstiles can be either waist-high or full-height and are typically operated by a token, ticket, or electronic card reader. They help prevent unauthorized access, reduce ticket fraud, and ensure the safety and security of the public. Turnstiles can also be used to count the number of people entering or exiting an area, providing valuable data for crowd management and planning.

The origins of turnstiles can be traced back to ancient times when they were used as a simple means of restricting access to certain areas. The modern turnstile, as we know it today, was invented in the mid-19th century and quickly became popular in public transport systems such as subways and trains. In the early 20th century, turnstiles became more advanced with the introduction of mechanical coin-operated models. As technology has advanced, electronic turnstiles with card readers and biometric scanners have become more common in everyday use.

Turnstiles are adapting to our fast-paced world. Modern versions, especially in transportation hubs, are incorporating contactless payment systems, like tapping a card or phone. Biometric features, such as facial recognition, are being tested in some places to speed up access without sacrificing security. For venues like stadiums, turnstiles now sync with ticketing apps, ensuring smoother entries. As our world prioritizes efficiency and safety, turnstiles will play a key role in managing crowd flow and enhancing user experience.