Lake Rotorua is the largest of the lakes with Lake Tarawera close behind, it is also the second largest lake in the North Island by surface area and covers 79.8 square kilometers. With a main depth of only 10 metres it is smaller than Lake Tarawera by water volume. The lake lies within a large volcanic caldera in the Taupo Volcanic Zone. After an eruption, the magma chamber underneath the volcano collapsed. The depression left behind is the Rotorua Caldera. Mokoia Island, is close to the middle of the lake and is the setting for the legendary tale of Hinemoa and Tutanekai.