Much of the housing stock consisted of apartment blocks built in the second half of the 19th century. Most of those, thanks to housing regulations and few elevators, were five stories high, built around a courtyard which could be reached from the street through a corridor large enough to take a horse and cart or small trucks used to deliver coal. In many places these apartment blocks were built around several courtyards, one behind the other, each one reached through the outer courtyards by a ground-level tunnel similar to that between the first courtyard and the road. The larger, more expensive flats faced the street and the smaller, less expensive ones were found around the inner courtyards.