Nagoya is a city famous for its castle.

Literal

Nagoya [topic-は] castle [for-で] famous city [copula-だ].

[X]で有名 = 'famous for X.' The particle で marks the reason/means of the fame. 名古屋城 (Nagoya Castle) is one of Japan's most famous castles, originally built in 1612 by Tokugawa Ieyasu's son.