"Impressions of the Berlin Wall"

Stop a random handful of Berliners on the street and ask where you might still find a stretch of the Berlin Wall in this, the 20th year since communism collapsed here. A surprising number will not have a clue.

Although much of the wall was razed soon after Nov. 9, 1989, sections that weren't given to museums, sold as souvenirs or ground into underlay for autobahns can be seen -- if you know where to go.

The longest stretch, just under a mile, is at the East Side Gallery, set up by Iranian artist Kani Alavi in the winter of 1989-90. Alavi persuaded more than 100 artists from 21 countries to paint their impressions on the eastern side. Two decades of pollution and weather have taken their toll, prompting Alavi to bring most of the artists back. Between now and October, you can watch them at work along Mühlenstrasse.