Five of the six Katz siblings from Nentershasen, in the mid-70s, in Quito, Ecuador.  From left Frieda, Moritz, Willy, Isidor and Joseph.  Julius had passed away in 1948.

  
The three sons of Willy Katz in 1999, while visiting Nentershausen.  From left Bert, Karl/Carlos and Manfred.
  
In 1973 Willy Katz and his wife Martha left their city of refuge, Quito, Ecuador to settle in Petach Tikvah, Israel.  His father, Jakob Katz II, had passed away, as well as his brother Julius, aunt Jettchen, aunt Elka, uncle Wolf and brother-in-law Leopold Hecht (spouse of sister Frieda).
Willy Katz sons left South America before their father. The oldest son, Siegbert (Bert), born in 1930, had moved to the USA.  There he qualified as an outstanding contributor at the Massachusetts Institute of Technology (MIT) in Boston.  As part of his professional activities, he participated in the Apollo Program as well as in other space and rocket projects. 
Manfred, one of the twins born on 8.18.1934, moved first to Israel and later in the 1960s to Hamburg where he opened a chain of restaurants.  In 1976 the newspaper “Bild” reported about him in an article (“That is the Way I Made my First Million!”).
Twin brother Karl/Carlos studied at the Polytechnic Institute in Quito, where in 1961 he obtained his degree in electrical engineering.

  
Click: Carlos (Karl) Katz and his wife visiting in Nentershausen (standing in front of the Town Hall