From April to August 2018, Kīlauea volcano, Hawai‘i, experienced the largest lower East Rift Zone eruption and caldera collapse in at least 200years. This activity included the destruction of the Halema‘uma‘u and Pu‘u ‘Ō‘ō lava lakes, up to 500m of collapse of the floor of Kīlauea caldera, the opening of 24 different fissure approximately 40km from the summit at Leilani Estates, and the production of numerous high-volume lava flows that ultimately reached the ocean. Many attributes of this activity have analogs to volcanic landforms and processes found on other planetary bodies, and so provide the potential for greater insight into caldera collapse, lava lakes, and pit craters on the Moon, Mars, Venus, Io, and elsewhere. Observations of the Kīlauea eruption also demonstrate the need for caution when using the preserved morphology of planetary lava flows to estimate mass eruption rates and duration between eruptions. Further, lava flows from Leilani Estates entering the ocean produced copious volumes of volcanic haze “laze” (a dense hydrogen chloride mist), and may provide a new explanation for the elevated chlorine levels detected by gamma ray spectrometers in Mars orbit.