Watch closely — because you might not see it again.

The Watchtower sign, a Brooklyn waterfront icon for 50 years, was taken down on Wednesday from atop the former Jehovah’s Witnesses building at 30 Columbia Heights.

The Watchtower Bible and Tract Society is moving to upstate Warwick. The nonprofit sold five Dumbo buildings last year for $340 million to a joint venture of Kushner Companies, CIM Group and LIVWRK, which plans to turn the properties into an office complex called Panorama.

The letters are each 15 feet tall and weigh up to 860 pounds. A sign named for a future office tenant will eventually replace them. The Witnesses will keep the old letters but it isn’t known what they’ll do with them.