Hotel das Cataratas, inside the Brazil side of Iguazu Falls, from here you can walk the trails and out to the overlook before the park opens! http://www.belmond.com/hotel-das-cataratas-iguassu-falls/
Iguazu Falls, Brazil side
Brazil side, prior to open hours (9AM) , but if you are staying at the Hotel das Cataratas, which is inside the Brazil park, you can walk out to the overlooks and be the only one there.