Forte San Giovanni was built between 1640 and 1644 just above the point where the valleys of rivers Pora and Aquila meet with the aim of strengthening defenses. The fort was adapted to the geographic topography and enclosed the ancient medieval tower linking the Finalborgo walls on Becchignolo hill. The work was directed by Ferdinando Glazer. This tower was recorded by the historian Filelfo and portrayed in a drawing of 1571.
The building developed with a pincer-shaped façade facing south, with high crowned walls with no openings, surmounted by a low parapet, and with suspended look-out towers on each corner. The fortress underwent other modifications directed by Spanish engineer Gaspare Beretta between 1674 and 1678. It was abandoned by the Spanish in 1707 and, under the domination of Genoa in 1713, it was partially destroyed. In 1833 it became a prison.
Since 1960 it has been public property and it has recently been completely restored.
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House of the Blackheads (Melngalvju nams) is a building situated in the old town of Riga. The original building was erected during the first third of the 14th century for the Brotherhood of Blackheads, a guild for unmarried German merchants in Riga. Major works were done in the years 1580 and 1886, adding most of the ornaments.
The structure was bombed to a ruin by the Germans June 28, 1941 and the remains demolished by the Soviets in 1948. The current reconstruction was erected from 1995 to 1999. Today the House of Blackheads serves as a museum and sometimes concert hall.