What is the best way to detect covered/hidden units in an enemy city?

The problem is that my invading naval force tries to defend my attacking "marines", however, sometimes an enemy destroyer pops out from no where and kills the unit.

This had perplexed me on occasion as to how this could happen. Especially since I utilize a defence with my navy where the only gaps would cause the enemy unit to move past my defence in an adjacent fashion, thus losing any remaining moves.

I have since worked out that the unit usually is within the city I am attacking and that I cannot see it because they are hidden/covered by a land unit in the city.

What is the best way to see the destroyer or any other units in the city when the rule of having multiple units on a hex is allowed?

Solution 1:

One way is to hover over the city hex and wait for the information bubble to show a list of units.

I have a series of screen shots showing the problem and solution.

In many scenarios it is not possible to see at all, however, this screen shot you may be able to make out the bow of a destroyer. Easy to miss!

Here is a close up.

The solution is to hover the mouse cursor over the hex of the city. (Not over the city name or the unit icon, the hex only).

Here is the strategic view where you can only tell there is more than one unit. You can hover your mouse over the hex here too.