A rounded mass of radicchio or lettuce is called what?

Which president is buried in the rose garden at his home in Hyde Park, New York? What word names a roue and his garden tool? What word names a round missile of war or a splashy jump into a pool? A round type of which farm structure, with the silo inside it, was popular in the early 1900s but is rare now? A row of purple seats rings which ballpark, marking a spot exactly 5,280 feet above sea level? A royal observatory was founded in which London borough in 1675? Which royal-sounding January 6 holiday shares its name with a 1999 George Clooney film? A royalist uprising in Paris was crushed by which young general in 1795?