Why did they make the Green Monster at Fenway Park?
Like most baseball stadia built before the mid-1950s Fenway Park was built privately in the inner city and confined to space available within a street pattern. That is why Fenway (and Chicago Cubs’ Wrigley Field) is so intimate and great to watch a game with the seats so close to the action. The distance from home plate to Lansdown Street beyond left field is comparatively short, hence the wall was built as an impediment to line drivs that would be caught in other ballparks becoming home runs at Fenway.