1.   Sewer manholes have been welded shut and all trash cans and mail boxes removed from the downtown area.

2.   Then they surveyed accessible sewer manholes that were potential problems.

3.   Authorities detained a man suspected of setting off the bomb, which was planted in a sewer manhole, Interfax said.

4.   One time he ordered police to leave the money in a container which he reached from underneath by a sewer manhole.