The document discusses time zones and timekeeping. It mentions extra fusos horários which refers to time zones, and escala which likely refers to a time scale or standard. It also mentions the Royal Observatory at Greenwich and the Greenwich Line, important concepts in the history of timekeeping and time zone coordination.

1. EXTRA FUSO HORÁRIO E ESCALA Professor Sérgio Saribera

2. FUSOS

3. Royal Observatory at Greenwich

4. Greenwich Line

10. ESCALA