Kroktjern-tunnelen
The tunnel was excavated in 1948 as a part of the water supply
for Oslo.
This cache is a tribute to the OlaDilt caches in Østmarka. In a
last attempt to find the 7th OlaDilt cache before it was published
Hysse, Tassen and I searched several places in Østmarka for the
cache. This place was my favourite guess.
More about the search for OlaDilt bonus cache here