What is associated with: 7 policeman were killed in 1886 when police tried to break up a workers meeting in this square?

Based on the clue '7 moons of our solar system are larger than this n...', what is the answer? Based on the clue '7 national medals of arts have gone to corporate p...', what is the answer? What is associated with: 7 of this rivers more than 1000 known tributaries exceed 1000 miles in length? Based on the clue '7 plus 1 completes the need', what is the answer? Based on the clue '7 presidents have lain in state nixon gave his fa...', what is the answer? Based on the clue '7 priests of the congregation of holy cross are on...', what is the answer? Based on the clue '7 seals 7 trumpets satan gets his dont add s to th...', what is the answer? What is associated with: 7 time nascar national champion died in last lap crash at the 2001 daytona 500?