Optical illusion makes this building appear to be on fire.

On Halloween night, firefighters in Ireland were tricked by an optical illusion when a building appeared to be burning.

The Dublin Fire Brigade posted a video of the illusion on Twitter, and it's seriously confusing the internet.

Take a look at the puzzling video.

While it looks like there is a fire in the second-storey window, the fire department explained that the building was not, in fact, burning. It was actually just the reflection of a "large bonfire in the city centre."

If you look closely, the fire is only a reflection - it's not inside the building.

Take a second look at the illusion and you'll see the reflection on the third floor as well.

The reflection is evident on both floors.

The department said that they responded to 337 fire calls on Halloween night - about 200 of which were Halloween related, like uncontrolled bonfires.

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