CuriosityStream

Best answer: CuriosityStream costs $2.99 a month or $19.99 a year for the high-definition service, or $9.99 a month (or $69.99 a year) for its premium 4K ultra-high definition service. That's after a free trial, of course.

CuriosityStream starts at $2.99 a month, with other options, too

CuriosityStream is home to more than 2,400 shows that span the categories of science, nature, history, technology, society and lifestyle. It's full of award-winning documentaries, and it has a host of exclusive original features and series.

It's also available on most any device you've got, including a web browser, Roku, Android, Amazon Fire TV, iPad and iPhone, Apple TV, Chromecast, Xbox One, and a number of smart TVs.

Pricing starts at $2.99 a month, if you prefer to pay as you go. Or you can pony up $19.99 a get a year's worth. That's for the standard-definition feed. For $9.99 a month — or $69.99 if you want to pay for a year up front — you'll get access to the 4K resolutions, too.

One caveat there, though: The 4K streams are only available in the web app, on Amazon Fire TV, Apple TV 4K, Chromecast, and on Roku. And not not all shows on CuriosityStream are available in 4K resolution.

Generally speaking, we like upgrading to 4K whenever possible. But given the price increase of more than 200 percent to bump up to 4K, this might be one of those times where it's OK to stick with the HD feed instead.

Our pick

CuriosityStream

For those who aren't afraid to learn a little

You can never have too much knowledge. That's where CuriosityStream comes in, with thousands of shows that are able to teach and entertain.

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