Barcelona Chair Mies van der Rohe  

Looks to be the white
..

Near as I can guess
based on any 'vintage' pictures I've seen, the leather was black.

1929
White

Although the cushions...
of the one in the MoMA have been replaced by Knoll for a thicker and slightly different version, the one in the MoMA collection is white....because the original two where white. Of course the recently reconstructed pavilion in Barcelona has white ones to.

What building is pictured?
What building is pictured?

.
Glace white and as an aside the originl Tugendhat chairs were mauve leather or fabric with a plaid like pattern, there was also some upholstery in the house that was acid green...chosen by Lilly Reich but I can't remember what. What I did really like was a couple of the Tugendhats had unbuttoned cushions which looked very good, actually with PU foam the buttons are pretty redundant now on both chairs.
The building is the Barcelona Pavillion, you should find about a million hits on it on google.
And as another aside a novel has recently been published set within the house, see link.
http://www.praguepost.com/tempo/2985-a-new-novel-set-within-the-looking-...

Thanks Health, I should've...
Thanks Health, I should've known that.

Tan....Luggage Tan..........
we purchased our vintage 1964 Barcelona group from an Eichler estate sale together with receipts, knoll catalogue pages and letters addressed to Mrs. F. Knoll.
Mrs Afra wrote to Mrs.Knoll enquiring what the original leather color of the Barcelona group showcased at the German Pavilion. Her letter was responded to by a staff member citing museum records indicate it was tan leather. The Afras purchased a Barcelona group that was as close as possible to the German Pavilion originals. The Knoll color was called tan luggage. The group included two Barcelona chairs an ottoman and coffee table which were delivered in 1964.