Proper nouns
Proper nouns include actual names like Robert, Thomas, Jürgen and Nina and the names of geographical features such as rivers and towns. In German as in English they have a capital letter.
(a) Proper nouns usually remain unchanged except in the genitive case where as -s is added as in English, but without the English apostrophe:
George's book, Georgs Buch
Simon's pencil, Simons Bleistift
Nina's car, Ninas Auto
Notice that feminine names add the genitive -s in the same way as the others.
(b) To form the plural of a surname, it is usual to add an -s, e.g. the Wilsons, die Wilsons; the Myers, die Myers
(c) Geographical names usually add -s in the genitive if the are maculine or neuter, but remain unchanged if they are feminine:
die Ufer des Rheins, the banks of the Rhine
die Geschichte Deutschlands, the history of Germany
but die Ufer der Donau, the banks of the Danube