It's a busy time for cruises to the Baltic, and for thousands of passengers the highlight is a visit to the former Russian capital of St Petersburg, which is a treasure house of palaces - not least the Hermitage, one of the biggest museums in the world.

In his ever-informative blog, Captain Albert Schoonderbeek, master of Holland America's Prinsendam, reports that on Thursday there were eight cruise ships in port. By my calculations that means more than 10,000 people setting out on excursions into the city, made all the easier because they can enter Russia on a group visa rather than having to be bothered with the rigmarole of organising the necessary paperwork individually.

But the number of visitors creates its own problems, as Simon Calder reports today in The Independent. Huge crowds flocking to the Tsarist summer and winter palaces, and the Cathedral of St Peter and St Paul, where numerous Tsars are interred, all put a strain on the city's limited public toilet facilities.

As one reader points out, the spectacular fountains of the Peterhof Gardens (left) are no help in this regard.

American institutions such as McDonalds and KFC provide one solution apparently, and entrepreneurs have been quick to spot an opportunity, charging the equivalent of 50p to spend a penny in portable toilet.  One other suggestion is to make full use of the facilities on the tour buses - as long as they are fully equipped.  It's something to bear in mind when planning the day's activities, especially for those intent on sampling the Russian vodka.