The Magellan planisphere, offered to the spanish King D. Carlos I, was possibly found
Luis Robles Macías, a former engineer passionate about the history of cartography and the discoveries, has written an insightfull and contextual article about the possible discovery of the Magellan Planisphere offered to D. Carlos I in 1519. This planisphere was thought to be lost during the Second World War. It was characterized as anonymous under the name Kunstmann IV, edited in 1859 by Friedrich Kunstmann.
The full story can be found in Spanish at the Luis Robles blog "Historia y Mapas" with the additional podcast.