‘Clear the sand from around my body’ … the Sphinx at Giza with the slab of hieroglyphs deciphered after the discovery of the Rosetta Stone. Photograph: Mike P Shepherd/Alamy

Our author discovers magic and malice on a code-cracking journey into antiquity as a new exhibit at the British Museum honors the momentous discovery that dispelled a 3,000-year-old enigma.

Out of Cairo, we are barreling north on broad, fast highways across a desolate terrain and into antiquity. After traveling for three hours, we arrive at Rashid, formerly known as Rosetta, a port city on the Nile delta. We enter Fort Julien and go through its interior in a circular direction until we reach the first corner, which marks the purpose of our voyage.

A world-changing discovery was made at this location in 1799. Lieutenant Pierre-François Bouchard of Napoleon's invasion force saw a black block of granite-like rock among the ruins of the fort's foundations. Given that Bouchard had worked with pencil inventor Nicolas-Jacques Conté, he readily understood the importance of the inscription engraved into the stone.

"Champollion rushed into his brother’s office, shouted ‘I’ve got it’ and then fainted"

This 762 kilogram piece of recycled granodiorite, which was used as a construction block, was engraved with an edict that King Ptolemy V issued in 196 BC. Although the message is relatively uninteresting, it is important to note that it was written three times: once in demotic, once in ancient Greek, and once in hieroglyphs, a gorgeous ancient Egyptian pictorial alphabet that is no longer understood (a known language).

Here, at long last, was the solution to understanding hieroglyphs—those exact representations of humans, animals, and things carved into stone or scrawled on papyrus thousands of years ago. Jean-François Champollion, who hurried into his brother's office and exclaimed, "I've got it!" before passing out and not being himself for five days, broke the code in 1822. The magnitude of his accomplishment is difficult to overstate: owing to this French philologist and a few other researchers, notably Thomas Young of the United Kingdom, 3,000 years of Egyptian history—one of the oldest civilizations in the world—came tumbling out into the open.

Also available as a snow globe … the Rosetta Stone at the British Museum. Photograph: Amir Makar/AFP/Getty Images

Ilona Regulski exclaims enthusiastically as she approaches a duplicate that is situated where the stone was found, "This is not only Egyptology. This marks the beginning of Egyptology. It is a striking location that is presently shadowed by the enormous spreading branches of a royal poinciana, sometimes known as a flame tree because of its vibrant red flower.

The British Museum in London, where the Rosetta Stone currently rests after being acquired from the French by the British army after they ended their war in 1801, is preparing to host a major exhibition on hieroglyphs, organized by Regulski, to commemorate the 200th anniversary of this seismic unraveling. The stone, a universally recognized emblem of all efforts to unravel the secrets of the past, is both the most popular and most commercialized item in the museum. The stone takes up a sizable portion of the sizable gift store, with its ground-breaking hieroglyphs adorning ties, nail files, mint tins, and snow globes.

With the help of 240 exhibits, including the Enchanted Basin, a granite sarcophagus whose hieroglyphs were thought to have magical properties and provide respite from the torments of love to anybody who bathed in it, Hieroglyphs: Unlocking Ancient Egypt will bring this rock star center stage. Hieroglyphs will reveal details of daily life in ancient Egypt along the route, including poetry, international agreements, grocery lists, and tax reports.

"This is the biggest open reading space in the world"

Regulski is leading a group of representatives from the British Museum and a few journalists on a quick tour to the region where the Rosetta Stone originated in order to have a deeper look at Egyptology and hieroglyphs. Our next destination, the Bibliotheca Alexandrina, one of the largest libraries on the planet, causes a buzz of excitement aboard the minibus. Its 2.5 million books—there is space for 8 million—are kept in an eye-catching 11-story building that overlooks the Mediterranean. Its sparkling sides are etched with enormous hieroglyphs, and its glass roof is slanted at 16.5 degrees to maximize natural light.

Our tour guide, Ranine Essam, tells us as we look about inside, "This is the biggest open reading space in the world." You certainly ponder how anybody can focus in such an exceptional setting. The ceiling windows are designed to resemble eyes, with shutters acting as the eyelashes. They are all supported by columns that resemble closed lotus flowers and are encased in a concrete shell that curves to absorb sound. Black Zimbabwean stone and oxidized Egyptian brass are used in the details to resemble elements found in ancient tombs.

Columns modelled on closed lotus flowers … the Bibliotheca Alexandrina. Photograph: Xinhua/REX/Shutterstock

Before we get to a large interactive exhibit, Essam rushes us through a series of dizzying spaces that are individually decorated with old and contemporary paintings and sculptures. The skeleton is revealed, with its arms crossed, amulets, earrings, and a piece in its mouth to hold it open in preparation for the afterlife. She manifests a dark blue coffin with a wave of her hand, making it spin and then shed its layers as we move from the inner coffin to the cartonnage to the wrapping.

The cartonnage and mummy of Baketenhor, previously thought to be a princess and now residing in Newcastle and its Great North Museum, which has lent it out, will be included in the British Museum exhibit, giving you a taste of what the genuine thing is like. Champollion described Baketenhor's inscription as a petition to a number of gods for the soul of the departed.

"The plate with three snakes took two years to engrave"

The program will also focus on the incredible tale of Ahmed Kamal Pasha, a curator who penned the first dictionary of ancient Egyptian words by hand practically as a hobby. In a lab in the basement of the Bibliotheca Alexandrina, its 20 volumes—two of which are missing—are now undergoing laborious restoration and preservation. Essam leads us inside, where groups of young ladies silently do their tasks at enormous tables covered with various-sized brushes, bottles, and scalpels. They are flanked by 21 enormous framed posters, each of which features four close-ups of different germs and fungi that may damage books.

The sanctification of the written word is astounding and invigorating, but the Bibliotheca was constructed to honor the Great Library of Alexandria, one of the greatest and most important libraries in antiquity, which turned the city into a major center of study and a capital of knowledge. There are 400,000 papyrus scrolls there, according to some estimates, covering everything from arithmetic and astronomy to physics and natural science. It is now lost to time and often thought to have been destroyed in a fire, albeit this is only partially true.

Do you want a bag with that? … Marvel’s Moon Knight, whose mild-mannered alter ego works at the British Museum gift shop. Photograph: courtesy of Marvel Studios/Disney

As our trip comes to a conclusion, Essam laughs and adds, "Now." "I want to ask you a question. How was the experience of filming Moon Knight at the British Museum? This is a reference to the Marvel superhero who fights really terrible ancient Egyptian gods and monsters before changing back into his amicable alter ego, who works at the British Museum gift shop, in the new Disney television series.

We go to the French Institute after we return to Cairo. Napoleon employed 2,000 painters throughout his war, and the 10-volume Description of Egypt was the result. This massive publication project took more than 20 years to finish. The institute's library curator, Agnès Macquin, dons a set of white gloves and walks us through a copy of the first edition.

When we get to the area with the incredibly detailed animals, she explains, "These three snakes took two years to engrave.

"Well, I believe they move. The first edition was printed in 1,000 copies, she continues. Only 200 units were sold in its first year because it was so expensive. The display will include a copy from the British Museum, which is not in color like this substantial, gorgeous document.

Topped with a vulture and a cobra … Tutankhamun’s mesmerising death mask. Photograph: Khaled Desouki/AFP/Getty Images

The Egyptian Museum is a beautiful pink stone structure on Cairo's Tahrir Square, and Regulski gives us a tour of it the next morning. As we pass a golden throne (complete with a footstool adorned with its royal owner's enemies) and a tall statue with a missing toe, she remarks, "This museum really is the mothership." Regulski pauses in front of a wooden coffin covered in hieroglyphs and mutters, "I could spend five years just studying this," before giving us an exciting running commentary in the Tutankhamun chamber.

People lined up all night long to get a glimpse of the boy-captivating king's blue and gold death mask when his treasures were lent to Britain in 1972, creating a sensation. According to Regulski, the snake and the vulture on top represent his authority over lower and upper Egypt, respectively. She then draws attention to the Book of the Dead spell etched in hieroglyphs on the mask's shoulders. The version of this funeral letter that Queen Nedjmet carried with her into the afterlife will be on display for the first time at the British Museum. It is elaborately decorated on a papyrus scroll that is more than four meters long and 3,000 years old.

“Queen Nedjmet also coordinated the murder of two policemen,” says Regulski. “If revealed on judgment day, these sins would have led to her eternal damnation. But in the papyrus, she appears brave and waits by the scales of justice for her heart to be weighed against Maat, the goddess of truth.”

No mention of murder … part of The Book of the Dead papyrus that accompanied Queen Nedjmet into the afterlife. Photograph: © The Trustees of the British Museum

Naturally, the anniversary of the discovery has prompted fresh demands from Egypt and Britain for the return of the Rosetta Stone. According to Professor Joyce Tyldesley of Egyptology at the University of Manchester, discussions to send it back and complete its journey might begin now, in the 200th year after the decipherment. Egyptologist Dr. Monica Hanna, who is in charge of a movement for repatriation, has spoken of "the people demanding their own culture back" in Egypt. The British Museum responds by stating that "no formal request from the Egyptian government to return the stone" has been made, and that 21 of the 28 slabs containing the order have still been found in Egypt.

As a dramatic conclusion, we ride the minibus to Giza to see the Sphinx and pyramids as they bake in the afternoon heat. Regulski directs our attention to the Dream Stele, a memorial slab with hieroglyphs that are no longer near enough to read, which is hidden between the latter's enormous lion paws. We have the original copy of this stele, she claims. It's quite accurate. The stele recalls the tale of Thutmoses IV, a youthful prince who came here to hunt when lions and hyenas roamed the area. As he slept off, the Sphinx appeared to him in a dream and said, "I will make you king of Egypt, but only if you clean the sand from around my body. Thutmoses, who wasn't in line for the kingdom, followed orders, took the throne, and had this tale tucked between his paws.

Until the code was broken and the Sphinx's voice could once again be heard for all time, it remained there in the restless sand for millennia, in plain sight but mute, its meaning lost to antiquity like the vast library.

From 13 October to 19 February, the British Museum in London will host Hieroglyphs: Unlocking Ancient Egypt. the Irish Linen Centre & Lisburn Museum in Northern Ireland, the Torquay Museum in Devon, and the Ferens Art Gallery in Hull. The British Museum funded Andrew Gilchrist's journey.

Thanks to Andrew Gilchrist at The Guardian whose reporting provided the original basis for this story.