While my daughter was in town this March, we took a weekend trip to Washington DC to see some sights. While checking out the monuments (and getting a little sentimental), I saw two interesting trench drains.
Trench Drain at the Lincoln Memorial Steps

These 4″ wide drains are filled with dirt and sediment, an indication that they probably are not pre-sloped. (Maybe, also, an indication of the maintenance budget.) I’m not certain they are really needed here, anyway.
The monument would look nicer if these drains were put into service again. Any patriotic volunteers to help clean these out?
Trench Drain at the Native American Museum
If you appreciate Native American culture and artifacts, this museum has something for you. I was impressed with a number of aspects of the building’s architecture. The granite trench drain grates running through the courtyard and water sculpture areas, in particular, caught my eye.
These grates are the most expensive pedestrian grates I’ve seen. Let’s not even talk about the percent open space for efficient water drainage. You can see they are ADA approved, but I’m not certain if they are heel proof. Are those holes 3/8″ diameter or smaller?