Yellowstone National Park is one of the most beautiful places on Earth.

Even just between the mountains and the wildlife, it would already be one of the most beautiful,

but there are other features here that make it truly unique.

The thermal features at Yellowstone, including the famous painted pot pools, are some of the most striking features found anywhere.

They almost don't even look like they're from this planet.

But, as is often the case, this beauty is deceptive.

Many of these pools bubble away at close to boiling and some are as acidic as battery acid.

I'm sure you can imagine what would happen if you were to fall in.

These are the horrific instance of Yellowstone National Park and as always, viewer discretion

is strongly advised.

Colin probably didn't think twice when he stepped off the boardwalk at Yellowstone National Park.

It's something plenty of people do, although they really shouldn't.

Maybe it's for a better photo, a close look, or just the thrill of exploring someplace you're not supposed to be.

Colin was 23 years old and visiting the park with his sister Sable in early June of 2016.

They'd made their way to Norse-Gyser Basin, an area known for its acidic hot springs and geysers,

and it's one of the most otherworldly places in the park. Steam rises from the ground,

strange colors bubble under the surface of the large pools, and the whole area hisses from the heat.

At some point, Colin and Sable left the path and walked into an off-limits zone. This seemed harmless

enough because they'd obviously be careful, even though they knew it was off-limits.

The problem was that the ground in these areas look solid, but actually isn't.

In this area, the land beneath your feet can crumble, and just beneath it is scalding, sometimes acidic water, hot enough to melt skin.

According to officials, the brother and sister were looking for a place to

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