HashtagsThe practice of using hashtags on social media originated on Twitter in 2007, primarily in tweets relating to forest fires in San Diego. may seem like a symbol of the modern age, but they could be far older than we think.

Archaeologists have found the oldest drawing ever discovered, dating back 73,000 years. It is a cross-hatch pattern sketched onto stone with an ochreAn earthy pigment typically varying from light yellow to brown or red. crayon.

It may look like a hashtag, but researchers do not know what the symbol means. Evidence suggests it is probably part of a bigger image: "It is definitely an abstract design [and] almost certainly had some meaning to the maker," claims professor Christopher Henshilwood.

The drawing predates other ancient artwork by up toThe drawing is 30,000 years older than the next oldest known paintings by Homo sapiens. However, wall art by the closely related species Neanderthals has been found dating back around 65,000 years. 30,000 years, suggesting that early humans developed creative impulses sooner than imagined.

"They were behaviourally modern," says Henshilwood: "they were able to produce and use symbolic material culture to mediate their behaviour, just like we do now."

The Blombos Cave, in which the drawing was found, has yielded many ancients treasures, including beads, stone tools, and seashells filled with red and yellow pigment (some call the cave a prehistoric paint factory).

It is just one of several locations that showcase the beauty and sophistication of prehistoric art.

Ghostly hand-stencils, over 30,000 years old, have been found in caves in Indonesia and Spain. "[They] do what nearly all art that would follow would aspire to," explains Simon Schama as he marvels at them in the BBC's Civilisations. "They want to be seen by others. And then they want to endure beyond the life of the maker."

Some millennia later came the extraordinary Lascaux cave paintings: over 6,000 depictions of animals, humans and strange symbols dating back 17,000 years.

However, it is not just creativity that we share with our ancestors. Prehistoric dog burials show that, like us, early humans used to keep dogs as pets (some were even buried with jewellery). Then there is the earliest known example of brain surgerySome prehistoric skulls have been found with incisions in the skull. Scientists believe these are the result of successful brain surgery because bone had regrown around the incision. - occurring 10,000 years ago just as the last ice ageA long period of time in which global temperatures are extremely cold. ended.

Of course, some argue. Ancient art proves that our oldest ancestors shared the same anxieties and impulses: from creativity to the desire not to be forgotten. Tweets, Snapchats, Instagram posts - they all contain the same subliminal message: "I am here!" Cave paintings preserve the same thing: an expression of presence and a desire to live on.

Nonsense, others respond. Through industry, economics and globalisation, modern man has broken decisively from the past. In fact, the day may come when we are no longer Homo sapiens at all. In the future, artificial intelligence could detach human consciousness from the physical world, and life could be lived entirely through computers and machines.