IARU Region 2 will grant the IARU-R2 AWARD to radio amateurs and radio listeners (SWL) who certify having contacted 20 countries or entities acknowledged in IARU Region 2, which corresponds to R2 of the International Telecommunications Union (ITU). Valid contacts must be made starting April 16, 1964, date at which IARU-R2 was founded.
The complete set of rules and the application can be obtained here.
Also available in Español (Spanish).