Plan your trip to be at Foz do Iguaçu in the full moon phase. Book the Full Moon Walk at Iguazu Falls in the Argentine side. Use the email: firstname.lastname@example.org. Even if you've been in the park during the day, at night is a completly and unique experience!
In the Brazilian side, you can do the Full Moon Walk only if you are staying at the Hotel das Cataratas.