Weihnachten customs held upon returning from church leading to the gift giving vary across the German-speaking countries. One of the most common situations sees the returning children wait to enter into their (locked) living room until a little bell rings. This bell marks the departure of the one delivering gifts. In the more Catholic regions - primarily South Germany and Switzerland - this is considered the Christ Child ("Christkind"), while those in North Germany commonly consider it to be the "Weihnachtsmann" (Saint Nicholas or Santa Claus) who is exiting. The children then enter to see the decorated Weihnachtsbaum (Christmas tree), with
Allen Tannenbaum Tannenbaum is a biophysicist and applied mathematician. Allen Tannenbaum Allen Robert Tannenbaum (born January 25, 1953) is an American/Israeli applied mathematician and presently Distinguished Professor of Computer Science and Applied Mathematics & Statistics at the State University of New York at Stony Brook. He is also Visiting Investigator of Medical Physics at Memorial Sloan Kettering Cancer Center in New York City. He has held a number of other positions in the United States, Israel, and Canada including the Bunn Professorship of Electrical and Computer Engineering and Interim Chair, and Senior Scientist at the Comprehensive Cancer Center at the University of