Recent experimental studies of the flux line lattices in type-II super
conductors are reviewed. All the experiments were performed using the
Bitter decoration technique which provides means of direct observation
of static vortex structures at the surface of the superconductor. Var
ious aspects of vortex behaviour that can be studied in decoration exp
eriments are considered, in particular vortex lattice ordering and the
effects of pinning and anisotropy on the equilibrium vortex arrangeme
nt. New vortex phases, such as vortex chains and oval vortices, which
were recently discovered in high-temperature superconductors, are also
discussed.