Calling to Earth Day Celebration 1:35

(CNN) -- More than half of the world's population lives in urban areas where nature can seem far away.

However, there are thriving ecosystems in our cities—even beneath our feet—and embracing urban nature can be a powerful force for change.

For example, for the first time in 400 years there is a dam built by beavers in west London following the reintroduction of a family of five beavers in October to a wetland on the outskirts of the city. Industrious beavers could help prevent flooding after heavy rains.

  • More than 200,000 people joined Call to Earth Day to promote care for our planet

Our Shared Home was the theme of the third edition of CNN's Call to the Earth, in which the network highlighted the crucial connection between cities and natural spaces.

Once upon a time there was a planet

Chacma baboons dominate Cape Town, South Africa, from a hillside. (Credit: Baboon Matters)

Interactions between city dwellers and wildlife are not always seamless.

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Cape Town baboons are often found rummaging through rubbish bins and backyards, putting them at greater risk of conflict with humans.

For primates, this behavior makes some sense: Suburbs encroach on their feeding grounds. Easy access to food from Cape Town's trash means that baboons spend less time and energy foraging for food and more on socializing with potential mates and the rest of their group.

However, this has consequences for baboons. Their health and well-being can suffer when they come into contact with dogs, cars, and power lines. Some baboons have even been shot.

The city began taking proactive steps to keep them away from the outskirts of Cape Town and into their natural hillside habitat.

Wild beavers are returning to the wetlands of west London for the first time in 400 years. (Credit: CNN)

Fantastic Creatures

Much of nature photography focuses on Earth's wild wonders and its majestic biodiversity.

Two photographers whose work CNN featured as part of the Call to Earth initiative took a different approach. They captured intimate images of wildlife in an urban habitat.

Photographer Corey Arnold discovered a bear burrow in the basement of a California home, while on the lush slopes of Hong Kong's New Territories, Lawrence Hylton filmed a scops owl owl, a white-lipped snake and an Atlas moth during his nighttime safaris through Shing Mun Country Park.

The astonishing, and sometimes funny, images show just how ready some animals are to adapt to a human-dominated landscape.

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