After four weeks of travel and years of planning, the Silk River has reached the end of its journey with the closing ceremony today at Kolkata’s Victoria Memorial.

There is something going on with the geography of Calcutta that I don’t understand. It ought to be simple.

Ask any British person where in the world they would like to go, at least once in their life, and I’ll bet that a visit to India would be at the top of the list. And if there was one experience that such potential visitors would specify, it would be a journey on Indian railways.

It’s our last day on the river today. We leave at seven in a fast-running tide that’s carrying rafts of water hyacinth along, some of them inhabited by pond herons.

After breakfast we take a bus through Barrackpore and get down near the river a few kilometres upstream from where we are staying. Then we walk down a small lane with walls on both sides.

Dawn eases the world into view from the boat. We are anchored off Chandannagar where today there will be a parade. It’s the best yet. We walk down The Strand with drummers and a team of acrobats on stilts wearing peacock feather headdresses.

During the night, when we are chugging downriver from Krishnanagar, there is torrential rain. Visibility at dawn is not much better. It’s what the Scots call dreich: thicker than mist, but not quite rain. In the wheelhouse, our pilot Nimai, is working hard to steer around the sandbanks, many of them invisible to ordinary mortals. But he sees them.

I like a town with a speciality. Nuremberg is wooden toys, York is chocolate, Buenas Aires is tango and London is second-rate politicians – no, hang on, every capital city seems to specialise in those.

Just before dawn we are on the riverbank about to be ferried out to our boat which floats offshore in the pearly mist. The sky and the river are same shade of grey. For once the world is hushed and almost silent.

One wonderful thing that happens when you travel through a landscape with something of a purpose is the chance encounters, the unexpected conversations that suddenly open up unseen worlds. Like with Darshan last night in Azimganj when he let slip about the elephant.