Before the Ted Williams and Tip O'Neill Tunnels and before the beautiful Zakim bridge there was a green monster more commonly referred to as Boston's Central Artery or elevated expressway that sprawled 1.5 miles and dissected the city cutting off entire neighborhoods from each other.
The pictures above are courtesy of the Massachusetts Turnpike Authority website. They show the central artery when it first opened in the mid 1950s and handled 75,000 vehicles per day and then again what the overly congested expresssway looked like 30 years later in the mid-1980s when more than 190,000 cars travelled this stretch every day.
I've included a second set of photographs (courtesy of Tufts University's Urban and Environmental Planning Policy website) that show how the city made a strategic (and I think excellent) decision to replace the elevated expressway with a beautiful garden now known as the Rose Kennedy Greenway. The park is still coming into its own but is a huge improvement and a welcome addition.