Urban densification has been presented as a general recipe to reduce travelling. The size of settlements was not considered particularly relevant in this proposal. Two arguments are presented that challenge the notion that densification of large cities leads to less travelling. The first is related to the internal dynamics of compact areas in large cities; the second to the dynamics between central and peripheral areas. It is shown that the densification of large cities leads to either more travelling because of the wide range of available opportunities provided by agglomeration effects, or more time spent on travelling due to congestion. The conclusion is that it is counterproductive for transport planning to endorse approaches that compact the urban form of large cities.