NYC Parks:

Prison Ship Martyrs Monument, Fort Greene Park

This impressive monument, consisting of a 100-foot-wide granite staircase and a central Doric column 149 feet in height, was designed by renowned architect Stanford White (1853–1906). The monument marks the site of a crypt for more than 11,500 men and women, known as the prison ship martyrs, who were buried in a tomb near the Brooklyn Navy Yard.
In 1776 American Major General Nathanael Greene supervised the construction of Fort Putnam on high ground that is now part of this park. During the Battle of Long Island, the Continental Army surrendered the fort and retreated to Manhattan. The British held thousands of captives on prison ships anchored in the East River. Over 11,500 men and women died of overcrowding, contaminated water, starvation, and disease aboard the ships, and their bodies were hastily buried along the shore. These brave patriots represented all thirteen colonies and at least thirteen different nationalities. In 1808 the remains of the prison ship martyrs were buried in a tomb on Jackson Street (now Hudson Avenue), near the Brooklyn Navy Yard.

AnimalNewYork.com :

While most people slept, a trio of artists and some helpers installed a bust of NSA whistleblower Edward Snowden in Brooklyn on Monday morning. The group, which allowed ANIMAL to exclusively document the installation on the condition that we hide their identities, hauled the 100-pound sculpture into Fort Greene Park and up its hilly terrain just before dawn. They fused it to part of the Prison Ship Martyrs Monument, a memorial to Revolutionary War soldiers. As of press time, the sculpture was still there.
The idea for the Snowden tribute was conceived about a year ago by two New York City-based artists with a history of pulling off notable public interventions. They linked up with a renowned sculptor on the West Coast who was sympathetic to their cause. The artists admit that Snowden probably wouldn’t approve of the project, since he never wanted the leaks to be about him, but they hope he’d understand why they did it. In a statement about the project, which they have entitled, “Prison Ship Martyrs Monument 2.0,” they wrote: “Fort Greene’s Prison Ship Martyrs Monument is a memorial to American POWs who lost their lives during the Revolutionary War. We have updated this monument to highlight those who sacrifice their safety in the fight against modern-day tyrannies….”

No word from Moscow on this gesture “against modern-day tyrannies”.

The 11,500 dead were unavailable for comment.