This is an odd solution to a sidewalk tree pit repair. Non-landscape
architects might not get it. The tree cracked the sidewalk, so they tore
that up & re-poured some fresh white concrete with a larger opening and
recycled the old concrete (it can look good stacked into retaining
walls) as a bulging herculean sort of thing. I prefer to think of it as
an artistic statement, and an effort to recycle but it may just be they
were cheap & didn't want to pay the contractor to make a dump run. It
probably keeps dogs from pooping there.

San Francisco, Castro above Clipper Street
Nikon D200 1/60 105mm f/8 ISO 100
Lens 105mm f/2.8G VR macro
Photoshopped to reduce glare & clone out some distractions.