The north of the municipality contains part (7.36%) of the 4,245,819 hectares (10,491,650 acres) Grão-Pará Ecological Station, the largest fully protected tropical forest conservation unit on the planet.[2]
It contains 10% of the 3,172,978 hectares (7,840,600 acres) Trombetas State Forest, created in 2006.[3]
Óbidos, Pará, in Brazil, was the scene of the sinking of Sobral Santos II in September 1981, one of the worst maritime tragedies in the history of the Amazon River. The riverboat was making its weekly trip between Santarém and Manaus and was claimed to be overcrowded when it sank in Óbidos harbour.[4] It is assumed over 300 people died in the disaster, with hundreds of bodies and body parts never identified.