Many believe the idea of a utopian society is an impossible fantasy.
But there may have been one mysterious, ancient group of people that was able to fulfil the dream of life without conflict or rulers.
Remains of the Indus civilisation, which flourished from 2600 to 1900 BC, show no clear signs of weapons, war or inequality.
Who Were the Indus
The Indus civilization flourished for half a millennium from about 2600 BC to 1900 BC, before it mysteriously declined and vanished from view.
It remained invisible for almost 4,000 years until its ruins were discovered by accident in the 1920s by British and Indian archaeologists.
Following almost a century of excavation, it is today regarded as a civilization worthy of comparison with those of ancient Egypt and Mesopotamia, as the beginning of Indian civilization and possibly as the origin of Hinduism.
More than a thousand Indus settlements covered at least 800,000 square kilometres (309,000 square miles) of what is now Pakistan and northwestern India.
It was the most extensive urban culture of its period, with an estimated population of one million and a vigorous maritime export trade.
This is according to Andrew Robinson. the author of 'The Indus: Lost civilisations', who has written an in-depth piece in the New Scientist.
'All signs point to a prosperous and advanced society – one of history’s greatest,' he writes.
The Indus Empire stretched over more than a million square miles across the plains of the Indus River from the Arabian Sea to the Ganges, over what is now Pakistan, northwest India and eastern Afghanistan.
Like their contemporaries, the Indus - who may have made up 10 per cent of the world's population - lived next to rivers, owing their livelihoods to the fertility of annually watered lands.
But the remains of their settlements are located in a vast desert region far from any flowing river.
They were forgotten until the 1920s, but since then, a flurry of research has uncovered a sophisticated urban culture with myriad internal trade routes.
So far, more than a thousand Indus settlements covering Pakistan and northwestern India have been discovered.
While multiple pieces of jewellery and the remains of various buildings have been found, not a single piece of armour or military weapons has been discovered.
Robinson points out that archaeologists have uncovered just one depiction of humans fighting, and it is a partly mythical scene showing a female goddess with the horns of a goat and the body of a tiger.
There is also no evidence of horses – an animal that late became common in the region - suggesting they were not use to raid other towns and cities.
In the almost 100 years since the Indus civilisation was discovered, not a single royal palace or grand temple has been uncovered.
Seriously Sophisticated Cities
The Indus Valley Civilisation possessed considerable skills when it came to town planning and building.
The cities of Harappa and Mohenjo-Daro are laid out in grids, with individual homes supplied with water from wells and waste water diverted to covered drains. This is perhaps the world's first known sanitation system.
Some houses had two storeys, a bath and courtyard.
The needs of cities were also catered for, with municipal buildings, marketplaces, dockyards, granaries, warehouses and protective walls to shield inhabitants from floods and attack.
Interestingly, unlike in Ancient Egypt, for example, no evidence of temples or places have been found, yet evidence suggests there would have been a social hierarchy.
It's thought most city dwellers were traders or artisans, with elaborate pottery, beads and metalwork recovered.
Speaking to Robinson, Neil MacGregor, former director of the British Museum, said: 'What's left of these great Indus cities gives us no indication of a society engaged with, or threatened by, war.
'Is it going too far to see these Indus cities as an early, urban Utopia?'.
While Mr MacGregor sees the utopian theory as credible, others cast doubt on the total absence of war.
Richard Meadow, Director of the Zooarchaeology Laboratory at the Peabody Museum of Harvard University, said: 'There has never been a society without conflict of greater or lesser scale.'
He argues that until the Indus script is deciphered, we cannot really know whether they lived this idyllic life.
Large societies are usually overseen by a central government, yet findings suggest otherwise for the Indus civilisation.
So far, the only sculpture that might depict a ruler is of a bearded man, dubbed the 'priest-king' – due to his resemblance to Buddhist monks and Hindu priests.
Many of the structures and buildings however, would have taken the coordination of tens of thousands of men, which some argue would have required a leader of sorts.
For example, Mohenjo-daro - an archaeological site in the province of Sindh, Pakistan - required a huge amount of man power to build.
Were The Indus Wiped out By Climate Change?
No one yet knows why such a great civilisation disappeared.
One theory, which emerged in 2012, is that climate change led to the collapse of the ancient Indus civilisation more than 4,000 years ago.
A study also resolves a long-standing debate over the source and fate of the Sarasvati, the sacred river of Hindu mythology, the authors believe.
Over five years an international team combined satellite photos and topographic data to make digital maps of landforms constructed by the Indus and neighbouring rivers.
They then probed in the field by drilling, coring, and even manually-dug trenches and samples were tested.
Co-author Dorian Fuller, an archaeologist with University College London, said: 'Once we had this new information on the geological history, we could re-examine what we know about settlements
'This brought new insights into the process of eastward population shift, the change towards many more small farming communities, and the decline of cities during late Harappan times.'
The study suggests the decline in monsoon rains led to weakened river dynamics, and played a critical role both in the development and the collapse of the Indus culture.
While the Indus might sound like they lived a utopian fantasy, the civilisation mysteriously came to an end in around 1900 BC.
Robinson believes the key in understanding this civilisation, is deciphering their script.
In an article published in Nature last year, he said: 'More than 100 attempts at decipherment have been published by professional scholars and others since the 1920s.
'Now - as a result of increased collaboration between archaeologists, linguists and experts in the digital humanities - it looks possible that the Indus script may yield some of its secrets.'