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It's not quite a war, but yes there is significant civil unrest in Columbia at this time.
Cartegena has been dropped from our Summit itinerary in late October, I presume it is also off yours (but check the web site). Actually several lines stopped visiting Cartegena a few months ago even before the current news headlines. It's too bad, this city has 500 + years of history sitting there to see.
We have seen that Cartagena has disappeared off the Summit October itinerary, sadly. We spent four days there a few years back after a visit to Ecuador, and if it does become safe again, would surely recommend a leisurely walk around the old city - take a cab and do it yourself rather than on a tour, as it's quite compact and easy to walk around and not get lost.