Cities change.
Sometimes it’s incremental and happens in just a few years:
This was the Transbay Terminal, at First and Mission Streets, up to last year, San Francisco’s hub of trains and buses at one time:
Soon, it will look like this.
And coming across Mission Street:
61 stories
This empty lot in San Francisco’s Glen Park neighborhood
Became this:
(I was the developer of this project, a combination grocery store, public library and housing.)
In 2016, this:
will become this:
San Francisco Museum of Modern Art expansion
The changes can take centuries.
This bucolic scene:
1802 – 1814
became this:
and wound up like this:
Rockefeller Center
In 1816,this was the scene at 16th and Dolores in the Mission, about 5 blocks from my apartment:
These changes are no big deal.
This year, on the site of the Transbay Terminal, a backhoe unearthed an 11,000-year-old tooth of a Woolly Mammoth. Today, tech workers and secretaries graze here on their lunch hours, but then it was this guy:
We marvel at the changing city – the restaurants opening and closing, the skyline changing. 11,000 years from now what eyes will gaze at First and Mission, and what will they see?
David Prowler Blog 
Water.