Here are a few shots of some of my favorite site details at Millennium Park.

I love the bench composed of separate 2x6s (or 2x8's-- I didn't measure it). It makes for a great ad-hoc work space or picnic area in a park that is skimpy on lawn.
This fence separates a lawn area from the Frank Gehry designed stage to the right.
Check out how the profile diminishes as the fence gains height.
The plant beds in Lurie Garden have stone retaining walls that are cut at an angle, so the appearance of a curb is minimized.
A slip guard as one approaches a bridge over the water that runs through the park, bisecting Lurie Gardens from the rest of the site.
The paths through the gardens are made out of small, long pieces of granite that vary in color between pink, peach, sand and white.