Cruises from San Diego to Hawaii often include a stop at Hilo. It is on the Big Island of Hawaii, and is one of the larger cities. Hilo is on the rainy side of the island, so the surrounding area is lush and green.
All of the rain produces spectacular waterfalls nearby. Don't miss Akaka Falls and Rainbow Falls. An excellent excursion is a ride on the Hamakua Coast drive from Hilo to Waipi'o Valley.
Most visitors to the Big Island are going to want to see the Kilauea volcano in Hawaii Volcanoes National Park, which is about 25 miles from Hilo. The volcano is active, so you can see molten lava, hot steam vents, and a summit caldera. The 2 minute video below has aerial views of the national park.