In our daily life, we encounter and interact with common yet beautiful objects. Two of these objects are locks and keys. Locks are fastening devices that are mechanically or electronically released by another object—generally keys. Locks have been used for over 6,000 years, with some of the earliest examples discovered in the ruins of Nineveh, an ancient city located in upper Mesopotamia, today referred to as Northern Iraq. In Egypt, pin locks were made of wood and fixed to doors. The Romans are largely attributed with popularizing the use of metal locks and keys, with the wealthy locking up their valuables and wearing the keys as rings. The first all-metal locks began appearing in Europe between the years 870 and 900. The industrial revolution not only modernized locks and keys, but made them more commercially available to everyday consumers. Today, locks and keys come in many forms, with the traditional pin-lock mechanism found on many of our homes, as well as key-less fobs used to electronically unlock cars or office buildings.

Locks and keys have played a significant role in storytelling over the years. In "Alice in Wonderland," Alice must drink a potion labeled "Drink Me" to shrink herself in order to fit through a small door to Wonderland. However, after becoming small enough to fit, she's not able to reach the key that will allow her to pass through. This leads her to consume a piece of cake labeled "Eat Me," which makes her a giant. She then cries a pool of tears, which floods the room, but eventually she's able to shrink back down again and pass through the key hole. In "Harry Potter and the Philosopher's Stone," Harry Potter, as well as his friends Ron and Hermione, must retrieve a flying key in order to retrieve the philosopher's stone and keep it from harm's way. Other examples of keys in popular culture include the Mondoshawan Tomb Key of "The Fifth Element," the Kingdom Key of "Kingdom Hearts," the Hatch Key of "Lost," the Copper Bones Key of "The Goonies," the Key to Erebor of "The Hobbit" and the Fleur De Lis Bank Key of "The Da Vinci Code."

Take a look at 75 lovely lock and key tattoos in the gallery below. Then let us know what unlocks the key to your heart in the comments section on social media.