Why can't I send a spy to a city?

[Nethog]

I'm playing the base game, and noticed that when I am selecting a mission for one of my spies, not all cities are listed for each civ. For example, there are 3 civs on the same continent as me, two of them have two cities each, and the third has three cities. For the civs with two cities, I can only send a spy to their capital city. For the civ with three cities, I can only send a spy to their capital and one of their other two cities. Seems random to me, can anyone explain why this is?

[Protok]

Need to have a vision on a tile with base which you want to spy on.

[Nethog]

Do you mean having a unit close enough to extend its sight to either a hex in the city territory, or the city center itself? And do I have to assign the spy with the unit currently in position with sight of the hex? Or as long as a unit extended its sight once to a hex in the city I can assign spies there later even with no unit with sight on the city hex? Actually all of the cities in my example are cleared of the fog-of-war, but I don't have a unit with sight of a city hex.

[dtt.scanner]

You can also use spy satellites to illuminate.

[Ryika]

Originally posted by Nethog:

Do you mean having a unit close enough to extend its sight to either a hex in the city territory, or the city center itself? And do I have to assign the spy with the unit currently in position with sight of the hex? Or as long as a unit extended its sight once to a hex in the city I can assign spies there later even with no unit with sight on the city hex? Actually all of the cities in my example are cleared of the fog-of-war, but I don't have a unit with sight of a city hex.

You don't need to have direct vision _now_, but you need to have had direct vision in the past. Cities founded in territory that you already have vision on will not become available for espionage automatically.

That's arguably a bug, but one you'll have to workaround.

[Nethog]

Ok thanks all. By the way I believe you have to have sight on the city center, not just a hex in the city's territory

[Ryika]

Yes, by "the city" people usually mean the tile with the city on it.