The world famous Waitomo Glowworm Caves are one of New Zealand's top tourist attractions, located just outside the main Waitomo township, easy to find and within easy reach of all local accommodation options. It is home to the famous Waitomo glowworms, Arachnocampa luminosa, tiny creatures that radiate their luminescent light. Formed over 30 million years ago, Waitomo Glowworm Caves have majestic and ornate cave decorations, deep limestone shaft known as the Tomo and the equally magnificent Cathedral cavern. The Cathedral is known for its superb acoustics, which are due to the enclosed shape and rough surface. Many famous singers, including New Zealand's own opera diva Kiri Te Kanawa, and choirs have performed here and have been delighted with the purity of the sound. The Tomo is one of the wonders of Waitomo, a 16 metre vertical limestone shaft which marks the course of an ancient waterfall which today only flows during heavy rains. The dramatic vertical drop is carefully lighted to show the scalloped walls and the layers of limestone. The Tomo was the last feature of the cave to be formed and links the upper level to the Waitomo River below.