Perched high above the teeming metropolis of Hong Kong, some of the city's poorest residents live in shanties that offer million-dollar views.

Known as "sky slums," the shanty towns have spread across the city, built on the roofs of previously existing apartments and tenements. Although they may have light and fresh air, the shacks have plenty of disadvantages. Residents must climb many stories of stairs to reach their homes and they contend with everything from bugs to flooding, said a PBS film.

Many of the illegal rooftop structures were built in the 1950s and 1960s when a wave of migrants from mainland China flooded the city of Hong Kong, reported CNN. The 2006 Hong Kong census showed that plenty of these migrants were still living in rooftop slums — 1,556 rooftop dwellings housed 3,962 people.

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Architect Rufina Wu and photographer Stefan Canham captured the slums with a series of drawings and photos in a book called Portraits from Above: Hong Kong's Informal Rooftop Communities. The two saw informal developments on roofs all over the city and visited with residents who sometimes hadn't been in Hong Kong long enough to apply public housing.

"Poverty is a feeling of hopelessness," Wu said in a documentary promoting the book. "There's nothing you can do to help yourself better your current situation."

Yet some residents are happy enough with their situation, especially because the government supplies the communities with postal service, electricity and water.

"People may look down on me, but I certainly don't look down on myself," said slum resident Lui Shek Lan to CNN.

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This picture taken on Aug. 7, 2013 shows a replica of the Eiffel Tower in Tianducheng, a luxury real estate development located in Hangzhou, east China's Zhejiang province. (STR/AFP/Getty Images)