Moeche Castle was built in the 14th century by the Andrades Family. It has an octogonal groundplan, and its walls are 10 m high and 3 m thick. Its gatekeep is 18 m tall and it is the only part of the castle protecting its walls from the outside. It was under siege and taken by the Irmandinos uprising.
The Moeche Castle has been restored recently, but in order to visit the interior of the castle, you'll have to request the keys from the local town hall.
References: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.