It is the larger genus Platanus for sure. Not likely London Plane (Platanus x hispanica - some publications call it Platanus × acerifolia . either way that species is a cross of Platanus occidentalis (American Sycamore) and P. orientalis (Oriental Sycamore). The reason I say not likely London Plane is because the balls are attached in twos. His pic in Post #15 has a row of 3. Not that it is impossible to have variability in nature! - but that is a identification separator.I'll go with Planetree.