Systems and methods for steering catheters to facilitate advancing the catheters through the body, wherein the catheters employ multiple steering stages, each of which can move in multiple planes. The steering stages are independently controlled to enable them to form complex shapes. In one embodiment, the steerable catheter includes an elongated catheter body with the steering stages incorporated into the distal end of the catheter. The steering stages may incorporate multiple memory wires and corresponding heating elements that control the temperatures of the memory wires and consequently control the shapes of the wires and the steering stages in which they are embedded. The catheter may be any type of catheter (e.g., a lumen catheter) and may include features that enable the catheter to perform functions such as delivering therapies (e.g., ablation) to target tissues within the body.