[KUL-TF]{}-98/17\
hep-th/9803231

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[*Instituut voor Theoretische Fysica\
KU Leuven\
Celestijnenlaan 200D\
3001 Heverlee, Belgium*]{}\
[Abstract]{}\

We construct a class of intersecting brane solutions with horizon geometries of the form $adS_k \xx S^l \xx S^m \xx E^n$. We describe how all these solutions are connected through the addition of a wave and/or monopoles. All solutions exhibit supersymmetry enhancement near the horizon. Furthermore we argue that string theory on these spaces is dual to specific superconformal field theories in two dimensions whose symmetry algebra in all cases contains the large $\cn=4$ algebra $\ca_\g$. Implications for gauged supergravities are also discussed.

Introduction
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During the last few years a new unifying picture of all string theories has emerged. All of them can be viewed as special limits of an eleven-dimensional theory, M-theory[@mtheory]. M-theory at low energies is described by eleven-dimensional supergravity ($11d$ SUGRA)[@11sugra]. This has led to an extensive study of the latter. However, most of the studies were confined to toroidal compactifications of $11d$ SUGRA. One reason for this is that in this case the connection with string theories is rather direct. These compactifications lead to Poincaré supergravities in lower dimensions. From the point of view of M-theory, however, there is 