Olive ridley sea turtles (Lepidochelys olivacea) arrive to spawn in Ostional beach, in Ostional National Wildlife Refuge, about 186 miles north of San Jose, on the Pacific coast of Costa Rica, at sunset on November 30, 2010. Massive arrivals of sea turtles, known as "Arribadas", happen in Ostional and members of the Integral Development Association of Ostional estimate that about 800 thousand may arrive this year to lay their eggs.