Ōpārara Arch is a huge natural limestone arch in Kahurangi National Park, reached by a forest walk from the Ōpārara Basin road. The river below is stained a deep tea colour by tannins, and the surrounding rainforest makes the place feel older and stranger than the short walk suggests.
The road in from Karamea is gravel and slow, so treat this as a proper outing rather than a quick roadside stop. It is still the single clearest reason to come to Karamea.