  This paper addresses the problem of exploring a region using the Hilbert's
space-filling curve in the presence of obstacles. No prior knowledge of the
region being explored is assumed. An online algorithm is proposed which can
implement evasive strategies to avoid obstacles comprising a single or two
blocked unit squares placed side by side and successfully explore the entire
region. The strategies are specified by the change in the waypoint array which
robot going to follow. The fractal nature of the Hilbert's space-filling curve
has been exploited in proving the validity of the solution.
