Combine two of londons great attractions with this flexible tour of the river thames and entrance to st pauls cathedral hop on and hop off your river sightseeing cruise from four conveniently located piers for 24 hours and explore the iconic cathedral designed by sir christopher wren whose history is steeped in the great fire of london and second world war see the city from the river and visit perhaps the most important feature on the london skyline a must do for london visitors included