Well, Tvdabadi is a small town in southern Sweden, a couple hours drive from Stockholm.

The roads are dotted with little barnhouses, painted bright red, blue and yellow ribbons,

the colors of the Swedish flag hang from flag poles and twist in the wind.

And just outside the town center, there's a lake.

I'm walking there on a Thursday afternoon, just before 1pm.

It's hot outside, literally not a cloud in the sky.

Some kids are doing cannonballs off the end of a dock.

An old lady and her grandchild are eating ice cream on a bench.

I sit down on a patch of grass and check my watch.

The clock is getting ready to strike one.

And that's when, suddenly.

I'm Sarah Lyman, and this is Atlas Obscura, a celebration of the world's strange, incredible

and wondrous places.

Today, we're visiting what is said to be the world's only functioning sun cannon.

It's a cannon fired by the sun.

Once a day, every day, we'll see it in person and learn how it works.

Right after this.

Sun cannons have been around since the 1600s.

Some of them were used on ships.

The position of the sun triggered them to fire at almost exactly 12pm, so everyone on board

would know what time it was.

In the 1700s, you might also have heard a sun cannon in a fancy park in England or France,

...