A replica of a Mercedes Benz 300 SL Gullwing Roadster all made of teak wood is displayed at the Frankfurt motor show IAA 2019, in Frankfurt am Main Germany, on September 11, 2019.

Frankfurt's biennial International Auto Show (IAA) opens its doors to the public on September 12, 2019, but major foreign carmakers are staying away while climate demonstrators march outside -- forming a microcosm of the under-pressure industry's woes.