The Historic City of Aden

The city of Aden was established within the crater of an extinct volcano, forming a natural horseshoe shape open to the sea on its eastern side, known as the "Front Bay." Together with its surrounding geographic landscape, Aden constitutes a cohesive socio-economic unit. As a historic port city, Aden has long been characterized by cultural plurality, functioning as both a recipient and transmitter of diverse influences. Its strategic location at the crossroads of international maritime routes has made it a focal point for trade and exchange between East and West, and a historic hub of commercial, cultural, and religious interaction.

Aden has historically served as a melting pot of civilizations, fostering coexistence and mutual acceptance. This is manifest in the peaceful living of diverse communities and the presence of churches, temples, and mosques across the city. The material culture of Aden includes archaeological remains that attest to its long and varied urban history, including defensive fortifications and commercial residential structures. Among the most significant monuments are Sira Castle and the Aden Cisterns (Sahareej al-Tawila), the oldest of which dates back to 1500-3000 B.C.

Since antiquity, Aden has functioned simultaneously as a city, port, and marketplace of both local and global significance. Its geographical position—commanding the vital maritime gateway to the Red Sea and situated along major international trade routes—has historically linked the continents of Asia and Africa. It continues to play a pivotal role in connecting Egypt and Europe on one side with India, China, and the African coasts on the other.

The city of Aden is distinguished by its unique architectural diversity, which is clearly manifested in its castles, fortresses, and defensive walls spread along its mountainous chain. This uniqueness also extends to its rainwater harvesting and management system, comprising three main components: the plateau, the cisterns, and the channels (locally known as "sailat"). The system begins with the plateau, which functions to regulate the flow of rainwater, channelling it into a series of cisterns and directing any surplus water through precisely engineered outlets via the sailat toward the seashore.

This system is considered a singular engineering marvel, having served for thousands of years—and continuing to do so to this day—as the first line of defence protecting the city from the dangers of flash floods. Additionally, it has historically supplied a significant portion of the city's potable water. The Tawila Cisterns, in particular, were constructed in a remarkable architectural and structural manner over many centuries, relying on the water-related skills and expertise of the inhabitants of southern Arabia, known for their mastery of floodwater management since ancient times.

The construction of these cisterns was based on an ingenious hydraulic system characterized by regulated drainage levels, and it took full advantage of the geological features of the site. The result was a highly sophisticated engineering design that harmoniously combined aesthetics, creativity, functionality, and thoughtful planning. Alongside this infrastructure, the presence of mosques, churches, and temples highlights the architectural and cultural plurality of Aden, reinforcing its exceptional value as a site of rich cultural interaction and heritage.

Criterion (ii): The architectural and urban elements of the city clearly reflect strong and mutual influences among human values, ethnicities, and religions. This is evident through the presence of mosques, churches, and temples, as well as the long-standing peaceful coexistence among the city’s inhabitants.

Criterion (iii): The buildings of the city of Aden stand as a unique testimony to the cultural traditions of a commercial city located on the southern coast of the Arabian Peninsula. This is exemplified by its sophisticated rainwater control system through the cistern network, the utilization of natural terrain, and its historical connection to the sea, being situated within the crater of a volcano.

Criterion (v): Aden provides an outstanding example of the relationship between a city, its port, and the sea, particularly given its location within a volcanic crater in an arid region. Through its innovative rainwater harvesting and management system using cisterns, the city represents a distinctive model of human adaptation and interaction with the natural environment.

Criterion (vi): The city of Aden is directly and tangibly associated with a culture of peaceful coexistence among diverse religious and ethnic groups, reflecting its historical role as a global commercial port city.

The landmarks of the city retain the authenticity of form and design, as clearly reflected in its architecture and the historic cisterns. This authenticity also extends to the materials and substance used, as well as the continued functional use of the buildings in accordance with their original purpose. Traditional management systems and techniques have been preserved, alongside intangible aspects such as language, spirit, and sense of place.

The historic city of Aden retains a sufficient number of its original buildings and landmarks, many of which remain functional to this day. There are no current threats posed by sustainable development projects that would compromise the proposed Outstanding Universal Value (OUV) of the city. All elements that contribute to the proposed OUV are present and adequately represent the city's historical and cultural significance.