Massachusetts December 20, 2020 11:38 pm Monolith Appears, Quickly Vanishes in Mass. City The monolith was discovered Saturday in the Quincy Quarries Reservation before it disappeared just a few hours later. US & World Videos 1:00 Three dead in apparent murder-suicide in Lowell 3:05 100 protesters detained at Northeastern University 2:39 Community mourns police sergeant killed on duty 2:50 Community mourns Billerica police sergeant killed on duty 4:32 Anti-war protester at Northeastern speaks amid arrests: ‘We are peaceful students'