In the area west and southeast of Washington, D.C is a grand trail that starts in the southeast at Mt. Vernon and continues along the Potomac River near Reagan National Airport and connects via Arlington County Trails to Washington & Old Dominion Trail all the way to Purcellvile, Virginia. Round trip, this is a 90-mile route. Please comment if this is not correct. But there is a section between Reston and Herndon in which roots have undermined the smoothness of the trail. In this case, they have created regular trail-wide cracks that cause an annoying bump every 25 feet or something. They look like roots that have caused cracks through which grass has grown anyway. This W & OD Trail is an amazing gift, but these little things slightly erode smoothness and speed. C'est la vie. Not only that, it is amusing to see yet another effort by humanity (even with regular upkeep and attention) get slowly destroyed by nature's relentless crawl against human artificiality.