The Lincoln Memorial Reflecting Pool is a popular spot for protests, celebrations, and photos. It's known for its peaceful atmosphere but also for its murkiness and gnat-filled air. Entering the pool has always been illegal, but enforcement usually was light. That changed after President Donald Trump claimed vandals damaged the pool's liner. Court documents refer to a June 9 incident in which a sharp object was said to have cut the liner. National Guard members and the U.S. Park Police have increased patrols near the pool. One man was arrested for touching the peeling paint. Crews have added fencing, which the administration attributes to July Fourth preparations.