If you are visting the Island of Hawaii aka Big Island don't miss Volcanoes National Park. Volcanoes is the most visited activity of the Island. Plan to make it a full day. Be prepared to do alot of walking in this park. You'll be glad you made the effort. The volcano is unpredictable, so don't expect it to be erupting when you visit. However, even when it is not active you'll enjoy the amazing lava landscape and lava pool.
For more information: https://www.nps.gov/havo/index.htm
Video of the lava lake activity in Halema‘uma‘u Crater on December 11, 2016 in the morning. This is a zoomed video from the observation deck at Jaggar Museum, which is about a mile from the eruption site.