For this reason black holes are invisible to the eye, as lightless as the empty, dark space surrounding them. Scientists know ...

Explore key animal rights issues and find out what activists are doing to make a difference.

Explore key issues and ideas in urban design and planning, including bike infrastructure, Vision Zero, walkability, density, and more.

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From van and bus conversions to trailers and tiny homes, discover the best in small living and find out how to downsize your own living space.

Learn how to clean up your beauty routine with safe, non-toxic makeup and skincare products that really work.

Learn what business and industry are doing to take responsibility for their impact on the planet.

See the pros and cons of everything from recycling to zero-waste – and find tips to reduce the trash and plastic that goes in landfills and incinerators.

Take control of your health and the planet's with expert tips on seasonal eating, shopping, proper storage, cooking, and reducing food waste.

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Lloyd Alter has been an architect, real estate developer, and prefab entrepreneur. He now teaches Sustainable Design at Ryerson School of Interior Design. Alter has been writing for Treehugger ...