Caption: Niels Bohr (1885--1962) and Albert Einstein (1879--1955) shooting the breeze.

This photograph was taken at Paul Ehrenfest's (1880--1934) house in Leiden, the Netherlands probably on the occasion of the 50th anniversary of Hendrik Lorentz's (1853--1928) Ph.D., 1925, Dec11.

Einstein is smoking a cigar, I think.

Credit/Permission: Paul Ehrenfest, 1925 (uploaded to Wikipedia by User:Stahlkocher, 2005) / Public domain.
Image link: Wikipedia: File:Niels Bohr Albert Einstein by Ehrenfest.jpg.
Local file: local link: einstein_bohr.html.
File: Einstein file: einstein_bohr.html.