Blue Hole (Big Pine Key)
The Blue Hole is an attraction on the island of Big Pine Key in the Florida Keys. It is an abandoned rock quarry that was used for nearby road fills and Henry Flagler's Overseas Railroad. The water it contains is mostly fresh and is used by various wildlife in the area, such as birds, snakes, alligators, key deer and green iguanas. It is part of the National Key Deer Refuge.
Blue Line (CTA)
The O'Hare Branch is the longest section of the Blue Line () and comprises both the oldest and newest segments of the entire route. The line starts at O'Hare International Airport in an underground station below the main parking garage, servicing Terminals 1, 2, and 3. The line emerges in the median of the O'Hare main access road (Interstate 190) just northwest of Terminal 5, about a mile (1.6 km) west of Mannheim Road. The line runs in the median of Interstate 190 east through Rosemont. The line has a stop at River Road in Rosemont, which is also the location of one of the line's two storage yards, then tunnels beneath the Kennedy Expressway/Northwest Tollway interchange near the Des Plaines River. The line runs in the median of the Kennedy Expressway (Interstate 90) until a point southeast of Addison Street. South of Addison Street, the line exits the freeway and enters a subway under Kimball Avenue. The line travels under Kimball Avenue and Milwaukee Avenues through Logan Square. South of Logan Square, the line emerges above ground onto an elevated structure parallel to Milwaukee Avenue. This section of structure, built in 1895 as part of the Metropolitan Elevated's Northwest Branch, is the oldest portion of the Blue Line, and the sole section of the line on an elevated viaduct. The three stations on this section (California Avenue, Western Avenue, and Damen Avenue) are also the only three stations on the line to use side platforms instead of island platforms.