Dreams are weird. Sometimes they’re vivid and cinematic. Other times, they’re just flashes of light and leftover thoughts from the day. They can leave us laughing, crying or confused, and we’ve been trying to figure them out for thousands of years.

Whether it’s an intense dream that wakes you up crying or a daydream of being someone important, the human experience of dreaming has always carried a little mystery. The way we think about dreams has changed a lot over time and across cultures.

Let’s take a closer look at how dreams have been understood throughout history. 

A dream is a succession of images, emotions, ideas and sensations that usually occur during sleep. Most dreams happen during the rapid eye movement (REM) stage, when your brain is buzzing with activity even though your body is at rest.

We spend around two hours each night dreaming, and each dream usually lasts between 5-20 minutes, though it might feel like it goes on forever. And while REM sleep is strongly associated with dreaming, some dreams happen outside of REM, too. We’re still figuring out exactly how and why they occur. The scientific study of dreams is called oneirology, and even with advanced technology and modern science, we’re still working with more questions than answers.

Long before modern science, people saw dreams as something powerful – often more powerful than waking life.

Let’s journey around the world and through time to explore the history of dreams. 

In ancient Sumerian and Babylonian societies (as early as 3000 BCE), dreams were etched into clay tablets. People believed dreams were direct messages from gods or the spirit world – and acted on them accordingly. 

In Mesopotamia, the practice of oneiromancy (dream divination) was deeply woven into culture, politics and medicine. A massive omen series known as Zaqīqu (sometimes called the "Assyrian Dreambook") included at least 11 tablets filled with interpretations, incantations and rituals designed to avert bad dreams – and they’ve been recovered from across Babylonia. To them, dreams could be spontaneous or deliberately induced, and scholars used a system of keywords to identify patterns and assign meaning. It went beyond dream journaling – it was a full-blown science of the sacred.

In ancient Egypt, dreams were considered deeply meaningful – so much so that they created a reference text for interpreting them, called the Dream Book. It worked like a dream dictionary describing dreams, labeling them “good” or “bad” and giving interpretations. 

It was believed that a person with vivid or intense dreams was spiritually gifted and Pharaohs would have priests acting as dream interpreters for them in case their dreams were prophetic. Dream interpreters were honored for their perceived ability to decode divine messages.

The same reverence for dreams appeared in ancient Greece and Rome, where dream interpreters often accompanied military leaders into battle. Dreams were treated like instructions from the gods – not to be ignored since many were believed to be prophetic, offering guidance about future events or warnings about what to avoid.

In traditional Chinese culture, dreams were often seen as supernatural – possibly caused by nature spirits or ancestral ghosts. In fact, during the Shang dynasty if a king had a disturbing dream, he would have his diviner consult the oracle about which ancestor or spirit caused the dream. It was believed that a dream could imply auspicious or inauspicious things, so the book Duke of Zhou Interprets Dreams would be used as a reference for dream interpretation. 

Many Indigenous cultures in North America have viewed dreaming as a way to connect with ancestors, the spirit world or life’s purpose. 

Among Iroquois and Ojibway people, dreams are brought by the spirit helpers of Creator in order to teach or warn of future events. Since dreams are believed to come from the spiritual world, they’re also seen as a form of communication with the dead, especially in order to heal grief. 

In West African cultures, dreams are regarded as direct messages from the spirit realm and could come directly from ancestors, nature spirits or even deities. The Yoruba people of Nigeria believe that dreams are a direct channel from Orun (the spiritual realm) to Aiye (the physical world) and the Akan people of Ghana consult dreams during major life events. 

With the rise of Western science in the 19th century, dream beliefs took a sharp turn. Dreams were increasingly dismissed as meaningless byproducts of stress, noise or indigestion. No messages from the gods, no spiritual journeys – just brain static.

But that wasn’t the end of us seeing dreams as more.

In the late 1800s Sigmund Freud, an Austrian neurologist, brought dream interpretation back into the conversation, but this time with a psychological lens. After a meaningful dream of his own, Freud developed his Dream Theory that a major function of dreams was the fulfillment of wishes.

Freud believed that dreams revealed unconscious desires and that analyzing them could help patients understand emotional struggles. His work laid the foundation for dream analysis in modern psychotherapy.

Today, scientists explore dreams using tools like EEGs and brain imaging – mostly focusing on what’s happening in the brain during different stages of sleep. REM sleep, for example, shows brain activity similar to wakefulness, and it's where most vivid dreaming seems to occur. Even if we don’t know exactly why we dream, the experience is universal, even across cultures and time.

Of course, not all dreaming happens at night. Daydreaming has long been part of the human experience, too. Once dismissed as lazy or distracted behavior, it’s now understood as a form of creative problem-solving or emotional regulation – especially when those daydreams of being someone important start to shape your goals or inspire change.

Nightmares – including crying dreams that wake you up crying – are also part of the spectrum of dreams. Some cultures still interpret nightmares as signs from the beyond, while modern science links them to stress, trauma or emotional processing during REM.

And while lucid dreaming – knowing you're dreaming while you’re in a dream – is a hot topic online (and in some scientific studies), it's not exactly new. People have been documenting lucid dreams for centuries, including in Tibetan dream yoga practices and early Greek philosophical texts.

And then there’s the classic “it was all a dream” twist – a literary and storytelling device that’s been around for centuries. From medieval tales to modern movies, dreams have been used to challenge reality, offer revelations or throw us a plot curveball.

So, why do we dream? That’s still up for debate. Some researchers believe dreams help us regulate emotions, consolidate memories or practice problem-solving in a safe, imaginary space. Others suggest dreams may allow us to process subconscious thoughts, or that they might not serve any specific purpose at all. We know a lot more than we used to, but dreaming remains one of sleep’s biggest unsolved mysteries.

From some of our earliest civilizations to modern day, dreaming – and being curious about our dreams – has been part of who we are. We’ve seen them as divine guidance, psychological clues, spiritual journeys and weird mental movies. And even though we no longer consult a dream priest after a particularly bizarre nap, dreaming is still something we all do – every night, all around the world.

And honestly? That’s kind of dreamy.