I checked out the Wikipedia entry on Nagoya and found out that it cites two sites as the City’s most famous tourist destinations: the Nagoya Castle and the Atsuta Shrine. Thanks to my wonderful hosts, I was able to visit both.
The entry says: “ Nagoya Castle was built in 1612. Although a large part of it burned down in the fires of World War II, the castle was restored in 1959, adding some modern amenities such as elevators. The castle is very famous for two magnificent Golden Orca (a type of fish) on the roof, often used as the symbol of Nagoya.”
(the moat the back of the castle


(the view from the top of the castle)
There were so many displays inside the castle . These were either descriptive of how the original structure was built -

Or many historical artifacts like this samurai armour -
Or a replica of the "golden dolphin" adorning the building's roof (which this foreigner had a grand time posing with) - 
"Atsuta Shrine is known as the second-most venerable shrine in Japan, after Ise Shrine. It is said to enshrine the Kusanagi sword, one of the three imperial regalia of Japan. It holds around 70 festivals in a year, and many people visit the shrine year-round. Also, the shrine has over 4,400 national treasures representing its 2,000 years' history.”
(the entrance gate where everyone has to pash thru: no passing from the sides)
(the cleansing well: visitors must must their hands or feet here before they proceed to the temple)
(the temple itself - throw a coin, then pray)

(the hall where elaborate Japanese weddings are held)
(the longest sword in the world)