What do these polygons mean on VFR charts?
To add a little to @abelenky's answer, you'll notice that each area has a identifier in it: SBR-522, SBP-505 etc. Those identifiers are made up of the ICAO country prefix, the airspace type, and a unique code. The airspace type can be Prohibited (P), Restricted (R) or Danger (D).

Since SB is the ICAO code for Brazil, SBR-522 is Brazil Restricted area #522; SBP-505 is Brazil Prohibited area#505 etc. I couldn't quickly see any nearby danger areas, but here's one in South Africa: FAD-193, near Port Elizabeth.

You can look up those codes in each country's Aeronautical Information Publication (AIP) or local equivalent to get more information about what each area is, what altitude it goes up to, any special rules etc.