PYTHEAS is an integrated robotic software system that offers advanced navigation capabilities, which include localization, workspace mapping, path planning and tracking and obstacle avoidance. PYTHEAS facilitates mapping of an unknown indoors environment by exploiting information extracted from a laser scanner. Based on this acquired environment representation, the system is able to navigate autonomously in the mapped environment, while, at the same time, avoiding dynamic obstacles such as moving persons, etc. All the required competences are coupled in an integrated system, which can be controlled through a user-friendly interface over the web. Extensive experimental results demonstrate the capability of the developed system to map complicated environments and support navigation in dynamic worlds.