Oratorio del Caballero de Gracia is one of the best hidden architectural treasures in Madrid. This church looks small from the outside, but inside it unfolds into a neoclassical temple by Juan de Villanueva, which looks like a Roman basilica.
Among its most noteworthy internal features are the single-piece granite columns, the vault and the sculptures of the Virgen del Socorro, signed by Francisco Elías in 1825, and of Cristo de la Agonía, which, according to studies, was made by Juan Sánchez Barba in 1650. The church belongs to the Caballero de Gracia Eucharistic Association, founded by Jacobo Gratiis (known as the Caballero de Gracia), who was born in Modena in 1517 and who died in Madrid in 1619. It is currently run by Opus Dei.
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.