The name "Waitomo" comes from the Māori words wai, water and tomo, hole or shaft. The local Māori people had known about the caves for quite some time before the local Māori Chief Tane Tinorau and an English surveyor, Fred Mace, did an extensive exploration in 1887.[citation needed] Their exploration was conducted with candlelight on a raft going into the cave where the stream goes underground. This is now the exit for the cave. As they began their journey, they came across the Glowworm Grotto and were amazed by the twinkling glow coming from the ceiling. As they travelled further into the cave by poling themselves towards an embankment, they were also astounded by the limestone formations. These formations surrounded them in all shapes and sizes.