  Galaxy interactions distort the distribution of baryonic matter and can
affect star formation. The nearby Magellanic Clouds are a prime example of an
ongoing galaxy interaction process. Here we use the intermediate-age
($\sim1$-$10$ Gyr) red clump stars to map the three-dimensional structure of
the Small Magellanic Cloud (SMC) and interpret it within the context of its
history of interaction with the Large Magellanic Cloud (LMC) and the Milky Way.
Red clump stars are selected from near-infrared colour-magnitude diagrams based
on data from the VISTA survey of the Magellanic Clouds. Interstellar reddening
is measured and removed, and the corrected brightness is converted to a
distance, on a star-by-star basis. A flat plane fitted to the spatial
distribution of red clump stars has an inclination $i=35\deg$-$48\deg$ and
position angle PA$=170\deg$-$186\deg$. However, significant deviations from
this plane are seen, especially in the periphery and on the eastern side of the
SMC. In the latter part, two distinct populations are present, separated in
distance by as much as 10 kpc. Distant red clump stars are seen in the North of
the SMC, and possibly also in the far West; these might be associated with the
predicted `Counter-Bridge'. We also present a dust reddening map, which shows
that dust generally traces stellar mass. The structure of the intermediate-age
stellar component of the SMC bears the imprints of strong interaction with the
LMC a few Gyr ago, which cannot be purely tidal but must have involved ram
pressure stripping.
