MERCEDES, Argentina: Part of the adventure was getting there. Our off-road vehicle jolted along the dirt road from the small city of Mercedes to the Ibera wetlands in north-eastern Argentina's Corrientes province. After 120 km, plenty of potholes and even more patience, we reached the hamlet of Colonia Carlos Pellegrini, gateway to Esteros del Ibera, a vast amphibious nature reserve teeming with flora and fauna.