Beat the Elite Four and the "Champion" (That's the most descriptive I can get to avoid spoilers)
You have to use the Unova Link, and you can use the Infrared connection with someone who has Pokemon Black 2 (which has Black City), and receive the key from them.
In the royal unova
The Unova Region. It is very, very far Region.
Shuckle is the #232 Pokémon in the new Unova Regional Déx, from Pokémon Black and White 2.
Pokemon Black and White take place in the new region of Unova. Just as the old regions like Kanto and Sinnoh are based on Japanese prefectures, Unova is based on New York City. You cannot visit any other regions in Black/White.
unova
You have to use the Unova Link, and you can use the Infrared connection with someone who has Pokemon Black 2 (which has Black City), and receive the key from them.
when you connect to other people's games through the highlink (entralink) you will unlock grass in white forest. The grass will hold Pokemon that are otherwise uncatchable in Unova.
dude unova is the region not a city
the evening
The Unova Region
unova is all
a region known from pokemon black and white.
The UNOVA Region
In the royal unova
you can get all the pokemon in the Unova region in pokemon black and white, in the other games you all the pokemon in sinnoh, hoenn, kanto and johto. Unova came out in 2010 and shortly after that they thought of a game / 2 involving Unova region pokemon.
in unova, about 7 legandary pokemon. in total, about 28.