Interesting Mercedes stuff.
Secondly this is an invitation to Christmas party in Johannesburg in South Africa. Many years ago we purchased a 1961 190c with an interesting history and this invitation in the glove box. The car was one of the first of the Fintail bodied 4cyl car to be made in South Africa. The owner was a journalist who was sympathetic to the civil uprising at the time. He claimed to have carried some of the leading political figures of that time in the back seat including Nelson Mandella. Anyway he had to leave South Africa in 1962 and migrated to Australia. He kept the car for another 30 years and sold it to us when he had the stop driving.
Over the years Mercedes-benz have made some very interesting cars, here is a photo of a test car that measures the road noise in a car. It is seen here testing a W114 or W115 chassis. This test was most likely done in 1967 as the car was released later that year. The car is based on a 300d (W186). This was the top of the line limousine from 1958 to 1962 when it was replaced with the mighty 600 (W100), usually reserved for heads of state and those with lots of money!