The Hanging Gardens of Babylon were one of the Seven Wonders of the Ancient World, as listed by Hellenic culture. They were described as an amazing engineering achievement, with step-like gardens that held many types of trees, shrubs, and vines. These gardens looked like a large green mountain made of mud bricks. They were said to have been built in the ancient city of Babylon, near present-day Hillah in Iraq’s Babil province. The name "Hanging Gardens" comes from the Greek word kremastós, meaning "overhanging," which refers to trees planted on a raised structure like a terrace.

According to one story, the gardens were built next to a grand palace called The Marvel of Mankind by King Nebuchadnezzar II of the Neo-Babylonian Empire (who ruled from 605 to 562 BC). He built them for his Median wife, Queen Amytis, because she missed the green hills of her homeland. This story was recorded by the Babylonian priest Berossus around 290 BC, and later mentioned by Josephus. Some sources also credit the legendary Queen Semiramis with building the gardens, leading to the alternate name "Hanging Gardens of Semiramis."

The Hanging Gardens are the only one of the Seven Wonders whose location has not been clearly proven. No ancient Babylonian writings mention the gardens, and no strong archaeological evidence has been found in Babylon. Three theories explain this: first, that the gardens were mythical, and ancient Greek and Roman writings (such as those by Strabo, Diodorus Siculus, and Quintus Curtius Rufus) described an idealized version of an eastern garden; second, that the gardens existed in Babylon but were destroyed around the first century AD; and third, that the legend actually refers to a well-documented garden built by Assyrian King Sennacherib (704–681 BC) in his capital city of Nineveh, near modern-day Mosul.

Descriptions in classical literature

There are five main writers whose descriptions of Babylon survive today. These writers focus on the size of the Hanging Gardens, their design, how they were watered, and the reason they were built.

Josephus, who lived from about 37 to 100 AD, wrote about a description of the gardens by Berossus, a Babylonian priest of Marduk. Berossus wrote about the reign of Nebuchadnezzar II around 290 BC, and he is the only source to say that king built the Hanging Gardens. Berossus described the palace with very high walls supported by stone pillars. He wrote that the king created a "pensile paradise" filled with many types of trees, making the view look like a mountainous area. He did this to please his queen, who was from Media and preferred living near mountains.

Diodorus Siculus, who was active around 60–30 BC, used texts from Cleitarchus and Ctesias of Cnidus, both 4th-century BC historians. Diodorus said the garden was built by a "Syrian king." He described the garden as square-shaped, with each side about four plethra long. The garden had tiers, with the top level 50 cubits high. The walls, 22 feet thick, were made of brick. The bases of the tiers were deep enough to allow roots of large trees to grow. Water came from the nearby Euphrates River.

Quintus Curtius Rufus, who lived in the 1st century AD, likely used the same sources as Diodorus. He said the gardens were on top of a citadel that was 20 stadia around. He also credited a "Syrian king" with building the gardens because his queen missed her homeland.

Strabo, who lived from about 64 BC to 21 AD, based his description on the lost writings of Onesicritus, a 4th-century BC writer. Strabo said the gardens were watered using an Archimedes’ screw that brought water from the Euphrates River.

The last known source is Philo of Byzantium, who wrote a book about the Seven Wonders of the World in the 4th to 5th century AD. Philo described the same water-raising method as Strabo. He praised the engineering and creativity of building large areas of deep soil far above the natural ground level and the irrigation techniques used.

Historical existence

It is unclear if the Hanging Gardens were real or a poetic creation. This is because there are no records from Babylonian sources from the same time period. There is also no mention of Nebuchadnezzar's wife Amytis (or any other wives) in historical writings. A marriage to a Median or Persian woman for political reasons was not uncommon. Many records describe Nebuchadnezzar's other works, but his long writings do not mention any garden. However, later writers claimed the gardens still existed during their time, and some of these accounts came from people who had visited Babylon. Herodotus, who wrote about Babylon in his Histories, did not mention the Hanging Gardens. It is possible the gardens were not widely known to the Greeks when he visited.

So far, no archaeological evidence has been found at Babylon that proves the Hanging Gardens existed. It is possible that evidence lies beneath the Euphrates River, but it cannot be safely excavated today. The river flowed east of its current position during Nebuchadnezzar II's time, and little is known about the western part of Babylon. Rollinger suggests that Berossus might have credited Nebuchadnezzar with the gardens for political reasons, and that the story came from another source.

Identification with Sennacherib's gardens at Nineveh

Oxford scholar Stephanie Dalley has suggested that the Hanging Gardens of Babylon were actually the gardens built by the Assyrian king Sennacherib, who ruled from around 705 to 681 BC, for his palace in Nineveh. Dalley believes that over time, people confused the two locations, and the gardens at Sennacherib’s palace were mistakenly credited to Nebuchadnezzar II’s Babylon. Archaeological findings have uncovered evidence of a large system of aqueducts, which Sennacherib’s inscriptions describe. Dalley suggests this system included an 80-kilometre (50-mile) network of canals, dams, and aqueducts that brought water to Nineveh. Water-raising screws were used to lift water to the upper levels of the gardens.

Dalley bases her arguments on recent studies of Akkadian inscriptions. Her key points include:

Sennacherib’s garden was famous not only for its beauty but also for the impressive water engineering that kept it alive. Assyrian kings had a tradition of building royal gardens. Earlier, King Ashurnasirpal II (883–859 BC) had created a canal that cut through mountains and planted orchards with fruit trees, including pines, cypresses, junipers, almonds, dates, ebony, rosewood, olives, oaks, tamarisks, walnuts, terebinths, ashes, firs, pomegranates, pears, quinces, figs, and grapes. A carved wall panel from Assurbanipal shows the garden in its full growth. The British Museum holds one original panel and a drawing of another, though neither is displayed publicly. Features described by ancient writers can be seen in these images.

Sennacherib’s palace had large limestone blocks used to protect against flooding. Parts of the palace were uncovered by Austin Henry Layard in the 19th century. His maps show shapes that match Sennacherib’s garden, but its exact location is still unknown. The area has been used as a military base recently, making further study difficult.

Watering such a garden required a major water supply for the city of Nineveh. Canals stretched over 50 kilometres (31 miles) into the mountains. Sennacherib proudly described the technology he used in his inscriptions. At the source of the Bavian (Khinnis) river, his inscription mentions automatic gates that controlled water flow. A massive aqueduct across the Jerwan valley was made of over two million carefully shaped stones. It used stone arches and waterproof cement. The inscription on the aqueduct reads:

"Sennacherib, king of the world, king of Assyria. I directed a watercourse over a great distance to the area around Nineveh, joining together the waters. I spanned steep valleys with an aqueduct made of white limestone blocks, and I made the waters flow over it."

Sennacherib claimed he built a "Wonder for all Peoples" and was the first to use a new method for casting bronze instead of the "lost-wax" process for his large bronze statues. He brought water to his garden from higher up in the mountains and used his new water screws to lift it even higher. This allowed him to create a garden that rose above the landscape, with tall trees on terraces, creating a striking visual effect that surpassed earlier gardens.

Plants

The gardens, as shown in artwork, had blooming flowers, ripe fruit, waterfalls that made soft sounds, and terraces covered with thick greenery. Based on Babylonian writings, traditions, and the natural features of the area, some of the following plants may have been in the gardens:

Plants that were brought from other places and possibly found in the gardens include cedar, cypress, ebony, pomegranate, plum, rosewood, terebinth, juniper, oak, ash tree, fir, myrrh, walnut, and willow. Some of these plants were hung over the terraces and placed along the walls, with arches beneath them.