Exploration of Mars, with the imprint & quot; MUESTRA & quot; - Block of stamps mint never hinged, catalog no. 2

The postal administration in Paraguay issued this block of stamps on the subject of "Mars exploration". The stamp pad appeared on October 8, 1973 and contains a stamp with a face value of 25 guaranis. This shows the NASA project "Viking". The stamp block is imprinted with "MUESTRA". The edition is 1,000 copies. Catalog no. 2487 f. 209

While exploring Mars, NASA sent two space probes (Viking 1 and 2) to Mars. The two space probes successfully landed on Mars in 1976 and sent images from the red planet to Earth.