Time in Nature in Costa Rica Found: 2 | Change Filter Options Explore the Irazu and Turrialba Volcanoes of Cartago Valley Explore two incredible volcanoes in Cartago Valley with local biologists. Visit Irazu's active crater and Turrialba's abandoned town. Rio Sierpe Mangrove Tour Explore the tranquil Rio Sierpe River mangroves, witness crocodiles and myriad bird species, and support the cooperative's efforts to preserve over 4,000 hectares of primary rainforest.