if london bridge were really falling down, into which river would it land?

London Bridge would land in the River Thames. Context:

• London Bridge spans the River Thames in central London, connecting the City of London with Southwark. The nursery rhyme “London Bridge Is Falling Down” is a traditional song about this very crossing, which historically crossed the Thames. Therefore, if it were to collapse, the most logical destination is the Thames itself, not any other European river.