Please Donate Blood Cache

The Please Donate Blood Cache geocache (GC1C90) was published by k2dave on 12 September 2001, the day after the attacks in New York. Its coordinates pointed at the site of the World Trade Center, but the listing warned that there was no point going there: you simply had to go and give blood, then log the find. "Your blood will be what you leave in this cache." It is the first locationless cache, or reverse cache: no box to look for, but an instruction to carry out anywhere.

Locationless caches did not last: a moratorium suspended new publications in February 2003, and on 3 January 2006 the fewer than four hundred locationless caches ever created were archived, their principle handed over to the Waymarking site. It is the only geocache type that can no longer be found.

k2dave kept the count on the listing, update after update. The last one, on 6 October 2001, announced thirty-seven recorded donations and fifteen promised, on the order of twenty-five litres. The logs speak of the crowds of those weeks: a call made less than two weeks after the attacks only led to an appointment on 25 October. Two caches in the same spirit had appeared in the days that followed, a candlelight vigil and a call for Red Cross donations; k2dave linked to them from his page, then removed the links as they were archived.

He archived his own on the day of that last update, admitting that it was not really a cache and recalling that people could go on giving without it. The page remained readable, with its encrypted hint that said nothing other than thank you.