Thanks for thinking of me while on vacation, Pierre! The center 2009 stamp features the UNESCO Neolithic site, Ggantija. It was excavated in 1827, but material has since been lost. Adjacent, are 2006 stamps from the 6v 'Ceramics in Maltese Collections'. A Red Skorba figurine is left and a medieval oil lamp holder at right.
Unfortunately these 1983 Europa stamps do not have their original tabs. Above is Ggantija, and below is Fort St. Angelo, which is thought to have been built over a fortified Roman settlement.
Thank you PaleoPhilatelie, for this 2004 Europa FDC! Ha ha this postcard-esque stamp on the right is so funny, did they really need to Photoshop these people in? They are standing in front of the c. 3600BCE Ggantija Temple on Gozo.