Lagos is the largest city in Nigeria, a fast-growing metropolis that has already spilled over onto adjacent waters but needs to grow up as well as as out.

Artist and architect Olalekan Jeyifous works in Brooklyn but grew up in Lagos, a place where patchwork urbanism and ramshackle architecture evolve out of necessity, invention and available materials.

In this series of imaginative photo collages, Jeyifous combines original photographs and three-dimensional models, envisioning a vertical expression of the same approaches.

In part, the imagery is a tribute to ground-up innovation and improvisation, which results in a vernacular often ignored by “serious” architects in favor of conventional design styles.

“The project examines the ways in which the nature of impoverished spaces,” says Jeyifous, “which are not only highly self-organized but also deploy sustainability practices as a matter of necessity, can be applied to cities undergoing massive population growth.”

Where some see horizontal slums currently (or vertical ones in this futuristic vision), others can find inspiration to create architecture that reflects all of the demographics and history of a given place.

A forced relocation is underway as thousands of squatters are moved by authorities out of their homes and the city of Caracas, some of whom have called the infamous half-finished Tower of David home for as long as seven years.

Rumors began a few weeks back as Chinese bankers expressed interest in purchasing the unfinished structure in Venezuela, with the intention of turning it back toward the (official and licensed) commercial and office uses for which it was originally intended. Currently, however, over 1,000 families live and work in the first few dozen floors of this 44-story skyscraper.

With surprising speed over the past week, the government has already shifted over 100 of these to a settlement outside of town (three floors a time) and is set to displace everyone living in the building, primarily to Valles del Tuy in the state of Miranda.

The tower was originally abandoned mid-construction in 1990 and eventually taken over by informal inhabitants who created not just homes but stores, offices, gyms, groceries, tailors, factories, churches tattoo parlors and even internet cafes within its walls.

Without an elevator (and with missing windows on the top levels), its most prized spaces for occupants have been on the lower floors, with scooter taxis that ferry people up ramps to some levels adjacent to the parking structure. Like Kowloon Walled City, the place has its own rules and informal systems of bringing in and sharing resources, including limited water and power.

The Urban Think Tank, which spent years studying the building (and writing Torre David: Informal Vertical Communities), has weighed in on the significance of the building and its occupants as well as its sudden shift in direction: “What we found was neither a den of criminality nor a romantic utopia. Torre David is a building that has the complexity of a city. It merges formal structure and informal adaptation to provide urgently needed solutions, and shows us how bottom-up resourcefulness has the ability to address prevailing urban scarcities.”

More from UTT: “When dealing with informal settlements, infusions of money for major public works and other approaches that involve large-scale rapid change – such as the razing of slums and relocation of poor populations – have generally failed in the complex setting of the city. The commercial housing market simply does not supply enough homes. There are too few units of social housing, and the majority of these are far beyond the reach of low-income families.”

“The dire asymmetries of capital in the global south do little to help; yet various forms of structural neglect have not always diminished great entrepreneurial vigor. Shunned by governments and the formal private sector, city dwellers, like those in Torre David, have devised and employed tactics to improvise shelter and housing.” Images via The Atlantic and Torre David: Informal Vertical Communities.

In some cities the slums run vertical while the rich build mansions on the precious ground, but in Mumbai, India, high-rise housing is considered premium real estate while the poor cobble together shelters below.

Alicja Dobrucka is the Polish photographer behind this photo series titled Life on a New High. Many of the photos were shot from a sufficiently high elevation to capture tall buildings on the backdrop of the surrounding urban landscape.

The residential towers stand in stark contrast to the sprawling ad hoc homes below, topped with a kind of (unfortunately) iconic patchwork of blue tarps.

Thousands of mid-rise-and-higher structures have been or are being built in Mumbai, often without regard for any overarching city plan. Some (like the famous one above) house single families on multiple floors, often with space for dozens of servants (in this case, reportedly, as many as 200).

Dobrucka also calls attention to the marketing slogans used to promote these structures. These catchy phrases are as seemingly out of touch with a their surroundings as the European-style architectural follies they are attached to: “You don’t just invite friends over, you invite awe”, “Ask yourself, how much envy can you endure? Neither wealth nor influence will bring them back again”, “If your tastes match with the President of France, we have just the right home for you”, “Other homes have works of art. Yours is one” and “Rooftop pool. Rooftop Jacuzzi. Rooftop lawn. As for the moon consider it complimentary”

These hidden shanty towns, often invisible from the streets below, sprawl like surrealist suburbs across the roofs of one of the most densely-populated and expensive cities in the world.

The book Portraits From Above meticulously documents a series of such informal micro-villages in Hong Kong with photographs, detailed diagrams and stories of life inside these illicit rooftop communities.

While the dwellings are unconventional in shape, the book’s drawings are almost deceptively refined, capturing the chaos in clean black-on-white architectural lines.

Ad hoc architecture at its strangest, these structures are not governed by building codes or compliance issues. Found materials from sheet metal and scrap wood to discarded plastic and broken brick shape home walls and the narrow halls between homes.

Naturally, one downside of such unplanned habitats are the series of power and waste management issues that go with the territory.

Despite living on the fringes – or perhaps because their shared connection – there are strong social ties between rooftop dwellers, and they were welcoming to the authors of this book, Stefan Canham and Rufina Wu, who sought to learn more about how people live in such offbeat accommodations. In many ways, too, these mini-cities are like smaller expressions of larger-scale phenomenon like the nearby but now-demolished Kowloon Walled City.

From the foreword: “There is no elevator. We run eight floors up the stairs … out of breath. The roof is a maze of corridors, narrow passageways between huts made of sheet metal, wood, brick and plastics. Steps and ladders leading up to a second level of huts. We get lost …. Rufina knocks on a door. A brief conversation in Cantonese. Stefan stands in the background, the foreigner, smiling, not understanding a word. They listen to us,  smile and invite us into their homes. Later, we look from a high building on the other side of the street down at the building [we were on before]. The roof is huge, with thirty or forty households, like a village. From the outside it is impossible to guess what it looks like on the inside.”

Later, “We walk back up the stairs. We no longer get lost in the corridors. We learn how the residents rebuild their homes and keep [them] in good shape. There are people who live for twenty or thirty years on the roof[s]. The newcomers from China, Southeast Asia [and] Pakistan still do it …. Some underlying buildings slowly disintegrate, because the concrete was mixed with salt water. Most residents roof would not mind to live in one of the new high-rise buildings, but they can not afford it. All are afraid to be resettled in the satellite towns, where there are few prospects. The rooftop settlements are an urban legacy. They tell of the history of Hong Kong, the political upheavals in China, renovation, and demolition speculation, [structural] calculations and what people need to live in the city.”

Take abandoned office towers without occupants, on the one hand, while people all around sleeping on the streets, on the other. One deserted structure in downtown Caracas provides a fascinating case study in this recipe for spontaneous urban reuse, its 45 floors now inhabited by over 3000 people.

The architects of Urban-Think Tank and photographer Iwan Bann joined forces to explore and document the Torre David office building that survived structurally (but not programmatically) the economic collapse of the mid 1990s in Venezuela.

There is some controversy about their exhibition at the Venice Architecture Biennale – critics claim it legitimizes local government misbehavior, or implies that the best example of regional architecture is a glorified ruin.

While there is some truth to these critiques, this occupation is also an example of a larger phenomenon worth studying around the world. There are good and bad lessons to be found in such instances of informal and impromptu architectural adaptations, about how buildings learn from the people that occupy them.

Basketball courts, workout rooms, production facilities, worship areas and community spaces and living areas all manage to fit in organically, dictated by the natural process of human needs and the communal negotiations around these.  There is, of course, a dark side to all of this too: a lack of safety and security both structurally and socially – it is necessary to look beyond the colorful pictures to see the grayscale reality of the situation.