Big John, the largest known triceratops skeleton, is being assembled in a showroom in Paris, Aug. 31, 2021. Before being put up for auction on Oct. 21, the more than 66-million-year-old Big John will be on display. Estimated between €1.2 million and €1.5 million ($1.4 million and $1.8 million), this remarkable specimen will be the centerpiece of the Naturalia auction organized by Alexandre Giquello at Drouot.