WW2 Pillbox - Craigavon - Northern Ireland. This casemate is of type FW3/26. During World War II, these bunkers were used for the defense of the United Kingdom against a possible enemy invasion. They were built in 1940 and into 1941.
Listening Stones, St. Vrain Greenway, Longmont, Colorado. Granite river boulders, wood, flagstone. 1997. This sculpture uses a parabolic sound mirror carved into boulders to dramatically magnify the sound of a nearby stream for listeners. The concept of sound reflection has been known for centuries, such as at the Whispering Wall in China.