35 1966 EBR-I Becomes National Historic Landmark After ceasing operations in late December 1963, EBR-I was dedicated as a National Historic Landmark on Aug. 26, 1966. A crowd of more than 12,000 people attended the dedication, which included President Lyndon B. Johnson (the first and, to date, only U.S. president to visit the Idaho Site).The landmark is open to the public for visits and tours from 8 a.m. to 5 p.m. seven days a week from Memorial Day weekend to Labor Day weekend. “ What happened here merely raised the curtain on a promising drama in our long journey to a better life.” — President Lyndon B. Johnson