Autonomous robotic systems for various applications including transport,\nmobile manipulation, and disaster response are becoming more and more complex.\nEvaluating and analyzing such systems is challenging. Robotic competitions are\ndesigned to benchmark complete robotic systems on complex state-of-the-art\ntasks. Participants compete in defined scenarios under equal conditions. We\npresent our UGV solution developed for the Mohamed Bin Zayed International\nRobotics Challenge 2020. Our hard- and software components to address the\nchallenge tasks of wall building and fire fighting are integrated into a fully\nautonomous system. The robot consists of a wheeled omnidirectional base, a 6\nDoF manipulator arm equipped with a magnetic gripper, a highly efficient\nstorage system to transport box-shaped objects, and a water spraying system to\nfight fires. The robot perceives its environment using 3D LiDAR as well as RGB\nand thermal camera-based perception modules, is capable of picking box-shaped\nobjects and constructing a pre-defined wall structure, as well as detecting and\nlocalizing heat sources in order to extinguish potential fires. A high-level\nplanner solves the challenge tasks using the robot skills. We analyze and\ndiscuss our successful participation during the MBZIRC 2020 finals, present\nfurther experiments, and provide insights to our lessons learned.\n