From the Wikipedia page [1]
Blackfriars Underground station is served by the Circle and District lines and is between Temple and Mansion House stations. It is in Travelcard Zone 1.
The station was opened on 30 May 1870 by the Metropolitan District Railway (MDR) as the railway's new eastern terminus when the line was extended from Westminster. The construction of the new section of the MDR was planned in conjunction with the building of the Victoria Embankment and was achieved by the cut and cover method of roofing over a shallow trench.
On 3 July 1871 the MDR was extended eastwards to a new terminus at Mansion House.
It was closed on 2 March 2009 for major renovation work and reopened on 20 February 2012.
The TfL page is [2]. More information here and here. A video here
See also Blackfriars Bridge Station, Blackfriars Road Station and Blackfriars Bridge Station