STEVE INSKEEP, HOST:
Good morning. I'm Steve Inskeep. One of the loveliest memorials in Washington is covered with grime. An invasion of microbes is spreading a black film over parts of Thomas Jefferson's memorial. The Washington Post says the National Park Service has not found out how to kill it. And the white dome now looks like a Dalmatian in need of a bath. Do not read larger meanings into this, folks, but we will long remember 2016 as the year that part of our treasured democratic heritage was covered with slime. It's MORNING EDITION. Transcript provided by NPR, Copyright NPR.