Things to see in Tokyo

Hi guys, am taking a trip to Tokyo for work, but am having 3 days down time, what can you suggest would be good activities, places to see while i am over there

Here: https://www.japan-guide.com/e/e2164.html

castles

when? (date)

male? woman?

What do u like to do in ur free time? (hobby, sports...)

any Japanese food that u want to eat? (allergy?)
any Japanese products/souvenirs that u want to buy?

if the weather is fine, u can see Mt. Fuji even fr Tokyo, tho.

watched vlogs?
https://www.youtube.com/results?search_query=100+things+tokyo

@SapphiraDragon
good ones all in out of Tokyo.
https://en.wikipedia.org/wiki/List_of_castles_in_Japan
Imperial Palace is not, no main building(tenshukaku).

A little off topic, but on castles: The ruin of Edo Castle is still able to be visited (and slightly interesting), but I believe the closest castle to Tokyo is at Odawara (rebuilt in the 1960s). The number of castles and fortifications registered is somewhere between 25,000 and 40,000 sites.

There's nothing really to do in Tokyo.

I'd just go home early.

Kamakura & Nikko.
https://www.japan-guide.com/e/e2166.html
https://www.japan-guide.com/e/e3800.html

Day trip is possible for both places, but overnighting in Nikko is recommended.