Metrorail is opening an hour early for the One Nation Rally in Washington this weekend.
Metro will open at 6 a.m. Saturday and operate extra Blue Line trains to accommodate the large crowd.
Organizers have paid Metro in advance for the early opening and additional rail service. Metro said groups have to pay $59,000 per hour for keeping system open later or earlier.
Crowded conditions are expected on all rail lines, but the biggest crowds are expected between Largo Town Center, Stadium-Armory and Pentagon stations on the Blue Line.