How ancient civilisations engineered urban life

In an age of smart cities, sustainable architecture and climate-resilient infrastructure, it would be easy to forget that the foundations of urban engineering were laid thousands of years ago. From the mountains of Peru to the floodplains of Cambodia, ancient civilisations built sophisticated cities that rival the best of today’s modern achievements. Communities in Machu Picchu and Angkor Wat, for example, were engineered to thrive in their unique environments. Despite being separated by thousands of miles and cultural differences, both sites demonstrate the same timeless principles - innovation, sustainability and harmony with nature.

Machu Picchu, the "Lost City of the Incas," is perched at 2,430 metres above sea level in the Andes Mountains. Far from being isolated, its location was chosen for strategic and spiritual purposes. The site offered natural defence and a sacred connection to the surrounding mountains, which the Inca viewed as deities.

The city was meticulously planned with distinct zones for agriculture, religious ceremonies and daily life. Agricultural terraces maximised the use of limited land and also prevented soil erosion to manage water runoff - a masterstroke in mountain engineering.

The Inca built Machu Picchu without the use of mortar. Instead, they employed a technique called ashlar masonry, using precisely cut stones that fit together seamlessly. This allowed the buildings to absorb seismic shocks and remain standing through centuries of earthquakes. It's a marvel of civil engineering that still stuns modern architects.

Despite its elevation, Machu Picchu had an advanced hydraulic system. The Inca constructed a network of canals, fountains and drainage systems that brought fresh water from nearby springs and prevented flooding. Beneath many buildings, engineers layered gravel to enhance drainage - a sophisticated approach that ensured the city's resilience against the elements.

Urban scale and monumental architecture

On the other side of the globe, Angkor Wat, located in present-day Cambodia, is the world's largest religious monument and the crown jewel of the ancient Khmer Empire. But it was only a part of a much larger city – Angkor - which spanned over 1,000 square kilometres, making it one of the largest pre-industrial cities in history.

The temple's design is a symbolic representation of Mount Meru, the centre of the universe in Hindu cosmology. It is surrounded by a massive moat and oriented in alignment with astronomical events, including the equinoxes and solstices.

Angkor's most groundbreaking achievement was its hydraulic infrastructure. Massive reservoirs called barays, along with an intricate network of canals and moats, were used to collect and manage monsoon water. This allowed the Khmer Empire to sustain agriculture during dry seasons and mitigate flooding during heavy rains.

The scale and efficiency of this system rival even today’s best practices in water management, highlighting how the Khmer transformed natural landscapes into living infrastructure.

The temple itself was built using sandstone blocks transported from quarries over 50km away, often floated on canals. The foundation techniques included layers of compacted soil and wood pilings to stabilise structures on the flood-prone terrain. Meanwhile, sacred geometry and astronomical alignment were embedded into the architecture, marrying form and function in a cosmological blueprint.

Angkor eventually declined due to a combination of prolonged droughts, intense monsoons and socio-political factors. Its collapse is a cautionary tale about the fragility of complex systems. Yet, it remains a powerful example of how infrastructure, spirituality and urban planning can harmoniously coexist.

Comparing two civilisations

Both cities used natural systems as functional infrastructure. Machu Picchu harnessed mountain runoff, while Angkor controlled monsoons. This is being mirrored today in "sponge cities," rain gardens and natural flood management systems. Machu Picchu’s earthquake-resistant buildings and Angkor’s flood-resilient foundations, also showcase how good design can mitigate environmental risks.

It should be noted that both civilisations considered cosmology, religion and environmental factors in their city layouts. Today’s urban planners can also take a cue to create cities that are not only efficient, but also meaningful and culturally resonant.

Whether it's the Inca using terrace farming or the Khmer using flexible water systems, adaptability was key. This is especially relevant today as cities face climate unpredictability and rapid urbanisation.

The so-called "lost cities" of Machu Picchu and Angkor Wat are not just archaeological wonders – they are blueprints for a better future. These ancient civilisations did not merely react to their environments - they engaged with them in ways that were intelligent, sustainable and deeply human.

As we look to smart cities, climate resilience and AI-driven design, we would do well to remember - the best ideas are often the oldest. In stone terraces and silent temples, the ancients left us a message. Listen closely, and you might just hear the future whispering back.