Berlin, Germany, 1939-1945
a website where people can leave their mobile phone number. The idea
is that when the number of people is large enough, a SMS instruction
is sent to all of them simultaneously by the server. When they receive
it, people have to perform the instructions. The instructions are
simple ones, like raising an arm, but the effect is amplified by the
fact that many people do it in the same place, at the same time, as
in a symphonic orchestra.