Massive (M_* ≥ 10^{11} M_&sun;) galaxies at high redshift (z ≥ 1.5) remain mysterious objects. Their extremely small sizes (effective radii of 1-2 kpc) make them as dense as modern globular clusters. It is thought that a highly dissipational merger is needed to create such compact galaxies. Within this proceedings, we discuss this issue, along with state-of-the-art morphological and kinematic observations of these objects. In the present day Universe massive galaxies contain large sizes, and harbour old and metal-rich stellar populations. In order to explore their development, we present near-IR IFU observations with SINFONI@VLT for ten massive galaxies at z ˜ 1.4 solely selected by their high stellar mass which allows us to retrieve velocity dispersions, kinematic maps and dynamical masses. We combine this with data from the GOODS NICMOS Survey, the largest sample of massive galaxies (80 objects) with high-resolution imaging at high redshift (1.7 < z < 3) acquired to date. As a result, we show how massive galaxy morphology changes possibly result through elusive minor merging.