1. Occupy Wall Street movement 1
2. oil tanker disasters 1, 2, 3
3. Ojos de Brujo 1
4. Ollé, Alex 1
5. El 11-M see Madrid bombings
6. Opus Dei 1, 2, 3
7. Ordóñez, Antonio 1
8. Ordóñez, Gregorio 1, 2, 3
9. O’Reilly, Karen 1
10. Organisation for Economic Co-operation and Development (OECD) 1
11. Ortega, Amancio 1, 2
12. Ortega y Gasset, José 1, 2, 3, 4
13. Ortiz, Letizia 1
14. Orwell, George 1
15. Otamendi, Martxelo 1
16. Otegi, Arnaldo 1
17. Otegi, Mikel 1
18. Otones 1
19. Oubiña, Laureano 1, 2