Several hundred residents living around a massive burning apartment complex construction site in the Mission Bay neighborhood of San Francisco were evacuated on Tuesday. Half of San Francisco's on-duty firefighters were called in as the inferno threatened nearby buildings. “The heat from the fire was making the windows pop and firefighters had to put up a water curtain to protect the buildings," explained Mindy Talmadge of the San Francisco Fire Department. According to Mayor Edwin Lee, an investigation has begun into what started the fire. Officials say the site will collapse after the amount of water used to combat the blaze.