Gymnasium (school) | gymnasium | Gymnasium | gymnasium (school) | Yoyogi National Gymnasium | Gymnasium (Germany) | Evangelisches Gymnasium zum Grauen Kloster | Theodor-Heuss-Gymnasium Heilbronn | Pancyprian Gymnasium | Mariinskaya Gymnasium | King Gustav Adolf's Gymnasium | Hölty-Gymnasium | Helene-Lange-Gymnasium | Gymnasium Jovan Jovanović Zmaj | Gymnasium (Denmark) | Friedrich-Ebert-Gymnasium | Chekhov Gymnasium | Tokyo Metropolitan Gymnasium | Taganrog's Boys Gymnasium | Stedelijk Gymnasium Leiden | Rysensteen Gymnasium | Rabanus-Maurus-Gymnasium | Pestalozzi-Gymnasium Biberach | Payne Whitney Gymnasium | Paul Roos Gymnasium | Memorial Gymnasium (Vanderbilt University) | Memorial Gymnasium | Lutheran Gymnasium Tisovec | Liaquat Gymnasium | Jelgava Gymnasium |
During World War II, Kohnstamm and Kessler were both held hostage by the Germans along with other prominent Dutchmen at camp Beekvliet in Sint-Michielsgestel; they became quite close there despite the difference in age.