Topic
- Crowds16
- Political campaigns16
- Social life16
- Spectators16
- Riot helmets15
- Truncheons15
- Students13
- Commencement ceremonies12
- Stadiums12
- University of Michigan. Phoenix Memorial Laboratory12
- Women12
- Cities & towns11
- Anti-apartheid activists10
- Anti-apartheid movements10
- Central business districts10
- Ice hockey10
- Ice hockey players10
- Nuclear reactors10
- Peace movements10
- Gas masks9