[Tuidjy]

As far as I am concerned there are two castles worth considering on land:

1. The watchtower - cheap in design points, cheap and quick to build, and a
stumbling block to any invader.
2. The castle - slightly inferior to the fortified city, as a castle, but cheaper
and much faster to build.

The wizard tower is a very nice castle, but costs 120 design points. Who can
afford this?! Everything else is crap. It is true that in a game of mine I am
getting frustrated besieging Mountain Citadels with 350 defense, but I cannot
help but think that maybe, if my opponent had taken a better castle, he would not
have had to man his capital's walls three turns after invading my lands. By the
way, Caelum fell, it just took four turns.

It is no wonder that in Multuplayer, you mostly see watchtowers. I would say
that the best players use them exclusively.