Harwood's Hole is a deep sinkhole located in the Marlborough region of New Zealand's South Island. It is known for being one of the deepest vertical caves in the country, with a depth of approximately 183 meters (600 feet). The hole is situated in the Abel Tasman National Park area and is surrounded by lush forest and unique geological formations. The entrance to Harwood's Hole is a narrow opening that leads to a series of underground passages and chambers. It attracts cavers and adventure seekers who are interested in exploring its depths. The site is also significant for its diverse ecosystem, which includes various species of flora and fauna adapted to the cave environment.