A Bad Idea

I know that beach-lovers want to live as close to the water as possible, but building below the high tide line is a Really Bad Idea. Some examples:

This staircase may not look too bad in this view,

but sand is unstable and has a tendency to wash out with the ebbing tide, leaving the entire structure above the soil and resulting in staircases like this one.

Sometimes, entire walls fail.

Streets intended to go all the way to the water don't always do too well, either.

With the possible exception of Neolithic stilt villages, building right on the water has not been one of humanity's brighter ideas.