Construction of the Seven Sisters Colliery, South Wales, begins; it is located on one of the richest coal sources in Britain.

Seven Sisters is a village and community in the Dulais Valley, Wales, UK. It lies 10 miles (16 km) north-east of Neath. Seven Sisters falls within the Seven Sisters ward of Neath Port Talbot county borough.

South Wales is a loosely defined region of Wales bordered by England to the east and mid Wales to the north. Generally considered to include the historic counties of Glamorgan and Monmouthshire, south Wales extends westwards to include Carmarthenshire and Pembrokeshire. In the western extent, from Swansea westwards, local people would probably recognise that they lived in both south Wales and west Wales. The Brecon Beacons National Park covers about a third of south Wales, containing Pen y Fan, the highest British mountain south of Cadair Idris in Snowdonia.

March 11 is the 70th day of the year in the Gregorian calendar; 295 days remain until the end of the year.