In a while these texts appeared on the image...
Alexander Calder's 113th Birthday
Courtesy of Calder Foundation / ARS, NY.
I did a search for...
Alexander Calder Foundation
... which brought me to this LINK...
Which introduced to me 3 generations of sculptors.
Alexander Milne Calder (1846–1923), American sculptor, father of Alexander Stirling Calder.
Alexander Stirling Calder (1870–1945), American sculptor, father of Alexander Calder.
The celebration on Google was for the latter, Alexander Calder (1898–1976), American sculptor and inventor of the Mobile Sculpture.