USSR 1964 cover, sent registered from Leningrad to Petrodvorets (now Peterhof). Registration label 'Leningrad' and purple boxed handstamp 'Zakaznoe' (meaning 'Registered'). The stamps are also cancelled with a special postmark of the Soviet Union dedicated to the 250th anniversary of Petrodvorets, dated 17.V.1964, and depicting the famous Sampson Fountain.