A former school known as S-21, this building became the hub of the Khmer Rouge’s interrogation and torture of more than 17,000 ‘enemies’ of the state. School rooms were turned into cells and today victims’ portraits align the corridors of this daunting building. This is an emotional visit, a place to pay respect to the victims of Cambodia’s tragedy.

Built between 527 and 565 AD at the foot of Mount Sinai for Emperor Justinian, this monastery later took its name from St Catherine of Alexandria, whose remains are said to rest here. It’s more fortress than church, with thick stone walls guarding the Church of the Transfiguration, the chapel of the Burning Bush, and a monks-only library packed with ancient manuscripts. Inside, you’ll find mosaics, religious ornaments, and some of the oldest illuminated manuscripts in the world on display. Outside, don’t miss Moses’ Well and the garden with centuries of history. The place is open most mornings but closed on Fridays, Sundays, and Orthodox feast days. Still active today, the monastery holds importance across Christianity, Judaism, and Islam, and continues its Greek Orthodox traditions uninterrupted.

The mangrove tunnels of nearby La Boquilla are an easy day trip from Cartagena. Guided tours will often combine a visit to the beach (one of the Playas De La Boquilla) with a boat or canoe tour of the mangroves, passing through Cienaga de Juan Polo and the Cienaga de la Virgen lagoons. Some tours will also include a closer encounter with local fishermen and offer insight into their craft. La Boquilla is an area of contrasts: the district of upscale hotels — Morros — borders on humble neighbourhoods populated by workers. When sitting down to tuck into no-frills seafood dishes served up by local eateries, make sure you're clear about the price of each item ordered from the get-go, as there have been reports of "surprise" bills amounting to several hundred US dollars.