Out of curiosity I did some research by way of Google… Pyrus calleryana Chanticleer or ornamental pear tree is otherwise known as a Callery or Bradford pear tree.
It hails from China, produces small, inedible fruits, and has greenish-white blossoms.
Its odour is said to be by many as identical to fresh semen. And it’s strong.
In 2005, it was voted Urban Tree of the year.
Apparently the Google HQ car park is surrounded by them.