How do I get to the tower, then?

Well, you have a general idea about what to do next:
Flood the city, that is.  See the previous question to figure out how.

Now the only problem is figuring out how to get across the lake you're
about to create.

Have you seen anything that might be suited for the job?

There was a boat above that restaurant.  If only you could free it ...
(See the appropriate question in the previous section for more details.)

Now, the boat is free to float, but unfortunately, it can float away.

So you need something to reel it in.

Did you look in the fishing rod in the restaurant?

Well, there's a fishing line that you can take.

You don't want to carry that line all the way with you around the city, so 
you had better find an easy way to get it near the boat.  Remember that the
boat is just below you (when you're on the overview of the city).

There is a hook conveniently placed on the high walkway.

So tie the line to the hook, and then let it drop.

Of course, you'll want to tie the line to the boat, and then you're ready!