Cappella dei Missionari del Preziosissimo Sangue is a later 20th century convent and college chapel at Via Narni 29 in the Tuscolano quarter.
A picture of the chapel on Wikimedia Commons is here.
The Missionaries of the Precious Blood used to have their Generalate (headquarters) at Santa Maria in Trivio. However, in 1964 they opened a huge new complex in a quiet suburban location near the Stazione Tuscolana. This was intended to be a seminary for the congregation as well as the headquarters, and was provided with a well-appointed chapel.
In 1972 they founded a parish, for which a separate temporary church was provided (a proper one followed in 1991 -see Santissimo Corpo e Sangue di Cristo).
The Generalate did not stay here, but at present (2018) occupies an unremarkable villa at Viale di Porta Ardeatina 66 in the Ostiense quarter. The congregational seminary, the Collegio San Gaspare del Bufalo (St Gaspare del Bufalo was the founder of the congregation), seems to be defunct. The premises are now occupied by the provincial headquarters and the Collegio Preziosissimo Sangue which is a retreat house (casa per ritiri).
The future of the complex is possibly in doubt.
The huge complex consists of three large flat-roofed modernist blocks, respectively three, four and five storeys tall. A peculiarity of the layout is that each has a very oblique angled bend in it, these angles pointing inwards. Two of the blocks are parallel and the third is perpendicular, occupying three sides of a rectangle if the angles mentioned are ignored.
A further set of two-storey ranges are fitted within the main blocks, and completely enclose an irregularly hexagonal central courtyard. The hexagon has sides of three different lengths, opposite sides being equal.
The roofs of these courtyard ranges are also flat.
The chapel looks very impressive from the outside, but is actually only the top storey of a three-storey building. This has a roughly pentagonal plan for the upper two storeys, with very obtuse angles at the sides. A very shallow three-sided apse is added to the back side of the pentagon, and is narrower than that side.
The ground level crypt storey is in red brick. Above, the main two storeys are in a pale yellow render. There are five bays, separated by massive exposed concrete piers which have a slight batter.
The front of the edifice abuts a two-storey range of the central courtyard. The third storey, containing the chapel, has two blank walls either side of a huge outwardly angled strut.
The side walls are blank above windows lighting the second storey. The chapel itself is lit by a large window in each side of each of the second to fifth bays, and these windows have slightly angled tops giving a low vertical zig-zag roofline.
The roof itself has a complicated design, and amounts to an attic storey. Each bay of the chapel has an attic pavilion, which are separate structures although they abut. The pavilions have roofs in light green. The middle three each have four gable pitches meeting at a point, and their height decreases from the second (the highest of all five) to the fourth. The first pavilion has a V-shaped reverse pitch over the angled strut on the frontage, creating a gully. The fifth pavilion has three additional gable pitches over the sides of the apse.
The side walls of these pavilions are blank, but there is a window strip tucked under each gable (except for the apse ones). There is a narrow strip of roofing in red between the pavilion side walls and the actual zig-zag roofline.
The interior is all in white. However, the windows contain brightly coloured semi-figurative stained glass. This applies to the main windows, and also to the very narrow inverted V window strips above them (the angles of the V's match those of the tops of the main windows).
The roof pavilions are open voids, separated by transverse inverted V support beams. The piers that support these don't feature much, but divide the narrow side spaces under the windows into cuboidal recesses. Because the pavilions vary in height, above each support beam is a low area of wall and each of these also has an inverted V window strip in stained glass.
The three-sided apse sports very impressive mosaics, designed by Marcantonio Bedini. There are three separate triangular-headed panels, with The Crucifixion in the centre. The Cross is accompanied by Our Lady and St Gaspare. The other two panels are abstract compositions, swathes of colour on a white background.
According to the convent's web-page on the congregation's website, Mass is celebrated on weekdays only at 8:00 and 18:00.