Tearing down a building

I liked this photo because it shows just how close they build things next to each other. On Bank Steet the workmen are taking down the outside of the demolished building by hand as not to damage the adjoining building. I understandhow they get this close with brick walls where they put them up by hand but how do they get so close when mostly machines put up the building. The downtown area is sure changing rapidly, and for the better I hope.