Invisibility

Another take on the definition or classification of what is invisible. While it may not be entirely relevant to any of our proposal now, it still provides some possible topics or mediums to explore. 

http://www.ted.com/talks/john_lloyd_inventories_the_invisible.html

Roosevelt Island

From the National Park Service:
"In the 1930s landscape architects transformed Mason’s Island from neglected, overgrown farmland into Theodore Roosevelt Island, a memorial to America’s 26th president. They conceived a “real forest” designed to mimic the natural forest that once covered the island. Today miles of trails through wooded uplands and swampy bottomlands honor the legacy of a great outdoorsman and conservationist."

This island sits in the Potomac River, just west of the city center.
Accesible only from the northbound lanes of the George Washington Memorial Parkway or via pedestrian bridge. In the middle of the island there is a bronze statue of Teddy Roosevelt and 4 granite tablets inscribed with his philosophies. 

Sonny Bono Memorial Park

Sonny Bono Memorial Park is a park in Northwest Washington, D.C., at the intersection of New Hampshire Avenue, 20th Street, and O Street near Dupont Circle. It is named for Sonny Bono. The park was established in 1998 after Sonny Bono's death by Bono family friend Geary Simon, a local real estate developer. He approached the D.C. Department of Parks and Recreation's Park Partners program and paid $25,000 of his own money to revitalize an unused 800-square-foot triangle of grass. His improvements included installing an underground sprinkler system, planting new Kentucky bluegrass and a Japanese maple, as well as benches and a wrought-iron fence. The park also features a vault of Sonny Bono memorabilia, such as the sheet music for "The Beat Goes On," his official Congressional cufflinks, and a mug from his string of Bono's Restaurants. 

 At the entrance, on the ground, is a plaque that reads as follows: "IN MEMORY OF MY FRIEND SONNY BONO 1935-1998; ENTERTAINER - ENTREPRENEUR - STATESMAN - FRIEND."

Vietnam Veterans Memorial

The Vietnam Veterans Memorial was designed by Maya Lin. Her concept was picked out of a pool of over 2000 applicants (The display board is pictured below). She wanted to create a park within a park - a quiet protected place onto itself, yet harmonious with the overall plan of Constitution Gardens. The walls have a mirror-like surface (polished black granite) reflecting the images of the surrounding trees, lawns, monuments, and visitors. The walls seem to stretch into the distance, directing us towards the Washington Monument, in the east, and the Lincoln Memorial, to the west, thus bring the Vietnam Veterans Memorial into a historical context. The wall is accompanied by a sculpture and a flagpole.

Each of the walls is 246.75 feet long, composed of 70 separate inscribed granite panels, plus 4 at the end without names. The panels themselves are 40 inches in width; the largest panels have 137 lines of names, while the shortest have one; there are five names on each line, although with new additions of names, some lines now have six. The walls are supported by 140 concrete pilings driven approximately 35 feet to bedrock; at the vertex the walls are
10.1 feet in height.

Henry "Box" Brown: Forever

Henry "Box" Brown was a slave who bought his freedom by shipping himself to freedom in a crate. Wilmer Wilson IV memorializes Brown by covering himself in stamps, going to post offices and asking to be sent. This was in D.C but clearly is not really a destination. Also, no word on what would have happened if any of the post offices complied with his request...

OWS/99%

That's not real, don't worry but it is a kind of memorial and very much invisible in that it is a joke from the Daily Show. I was legitimately shocked, however, that this was all I found when I was searching for a memorial for OWS or the 99%.

Ghost Bikes

Pretty self-explanatory. They have an entire website and they are in many different countries.