The series found that Boston colleges have added thousands of students without enough housing to accommodate them all, pushing students into dangerously overcrowded apartments in surrounding neighborhoods and putting students' lives at risk. A Globe team discovered that overcrowded apartments were rampant in student neighborhoods, including many that were firetraps or riddled with pests, broken locks and other hazards. Local colleges reneged on promises to building more housing and steered students to one of the city's most notorious landlords. Local housing regulators seemed powerless or unwilling to tackle the issue. And families were gradually replaced by absentee landlords, changing the character of key parts of the city.