On 7th January 1785, Jean-Pierre Blanchard and John Jeffries performed the very first successful balloon flight across the English Channel (La Manche), covering the route from Dover Castle to Guînes (Guisines), Pas-de-Calais.
(full story available here)
Cover photo: Arrival of Mr. Blanchard from his 38th air journey to the city of Groß Enzersdorf, copperplate engraving by Johann Hieronymus Löschenkohl (source: Wien Museum Inv.-Nr. 62014, CC0)