The tour I went on organised by La casona hostal was also good. Its a great experience, with my safety hat on; perhaps not ideal. The guide from La Casona, as part of the dynamite demonstration, it the safety fuse (plus of 4 mins) in front of us, then chatted (and showing off) & then went around the corner to put it into another tunnel. if on Casona tour tell him to light it around the corner - from my army days people being relaxed and casual with explosive are highly dangerous and it can end in disaster.
(held in London)
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