The obverse of the coin at the top the emblem of the USSR of the sample of 1956 (15 bands of tape around the number of the Union republics, the lower coil larger than the other). Under the emblem of a large letter "СССР" yet below is the value: a large figure "3" under it the word "РУБЛЯ" At the very bottom near Kant is the year of issue "1990". In the bottom left, under the horizontal line in the two lines marked metal, fineness and weight of pure silver - "Ag 900 to 31.1" on the right side under the same trait located at the same level, is a mark of the Leningrad mint (stylized letters "ЛМД".
On the reverse in the center the relief image of the Peter and Paul fortress in St. Petersburg, in the foreground a sailing ship and a boat. Upstairs along the rim, a semicircular inscription: "500-ЛЕТИЕ ЕДИНОГО РУССКОГО ГОСУДАРСТВА" down more finely along the rim "ПЕТРОПАВЛОВСКАЯ КРЕПОСТЬ • 1703Г."
On the front and back parts of the coin along the circumference has a raised rim.
Shown here are specimens from the Museum of the Goznak "History of money" Saint-Petersburg mint
Peter and Paul fortress founded in 1703, that date is also the date of the founding of St. Petersburg. At first the Fort was wooden, and under Catherine II, it was blocked with a stone, after that I found a modern look. From 1730 every day at noon from the Naryshkin Bastion is a blank cannon-shot. The tradition was interrupted only for a short period (1934 and 1957). From 1731 on the Flag tower began to raise St. Andrew's flag (except 1917-1990). The fortress is the Peter and Paul Cathedral which is the burial place of all Russian emperors and members of the family (except Peter II). Also on site is a Grand tomb, several museums and the mint is the oldest operating in Russia.