Social media was perplexed this week when a mysterious light was seen inside an New Orleans hospital that had been abandoned since 2005.

In the photograph that made rounds online, the light can be seen among hundreds of darkened windows at Charity Hospital.

Some thought the glow was coming from a Christmas tree inside.

Employees at Tulane Medical Center across the street first noticed the glow, which was coming from the upper part of the building.

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"It was pretty neat, but also a little creepy," Tulane anesthesiology technician Michael Arbon said to ABC News.

Police investigated what they later called a break-in and said the glow was actually 2-by-4-foot wooden boards wrapped with lights, according to Louisiana State University director of information services Leslie Capo.