Mokuaikaua Church is the oldest Christian church in the Hawaiian Islands, completed in 1837 by Hawaiian Christians under the direction of the missionaries from the Thaddeus mission. The dark lava-rock walls are nearly four feet thick and the bell tower is the tallest structure on Alii Drive, visible from across Kailua Bay.
The interior is austere — bare lava-rock walls, koa pews, a small organ — and gives a strong sense of the missionary era of Hawaiian history. A small museum at the back covers the history of the Thaddeus mission, the Hawaiian Bible translation, and the building's own construction. The church remains an active congregation; Sunday services are held in both English and Hawaiian.