Now on display in Paris in the Gallery of Paleontology and Comparative Anatomy (sadly, in a stairwell), it’s an excellent fossilized skeleton of a Palaeotherium Magnum:
Palaeotherium is an extinct genus of quadrupeds, most closely related to modern-day tapirs and horses. Based on the large number of their fossils that have been found to date, they widely roamed the forests that covered western Europe some 45 million years ago. But Palaeotherium browsed on low-hanging leaves (up to about 1-1/2 meters above the ground), leaving it at a disadvantage when Europe dried out, and the ancient forests were replaced by grasslands.
Most species of Palaeotherium were small, measuring about 75 cm (2-1/2 feet) tall at the shoulder. Palaeotherium Magnum was the largest of its kin, nearly reaching the size of a modern-day horse.
Courtesy of the Smithsonian Air & Space Museum’s Udvar-Hazy Center, here are two small bits of history you’ve likely never seen before — arming plugs for the “Little Boy” atomic bomb:
From the placard:
Small metal plugs were used by the Enola Gay weapons officer to arm the atomic bomb dropped over Hiroshima on August 6, 1945. He removed three green plugs that kept the firing circuitry inactive and replaced them with red plugs that closed the circuits. These plugs were found in the navigator’s compartment of the Enola Gay during restoration. It is not known whether the green “safe” plug is from the “Little Boy” atomic bomb or was used on a practice mission. The red plug was probably a spare.
Courtesy of the Smithsonian National Air and Space Museum’s Udvar-Hazy Center, it’s (a very good replica of) thePioneer5spacecraft:
Pioneer 5 (a.k.a. Pioneer P-2, and Thor Able 4) was launched on March 11, 1960 on a Thor-Able rocket, to explore the space between the orbits of Earth and Venus. It wasn’t a particularly large spacecraft by modern standards, weighing only 43 kg (94 lb) — but it provided the first maps of the interplanetary magnetic field (which had only been suspected to exist), and gave scientists new measurements of cosmic radiation.