Observations show that star formation is an inefficient and slow process. This result can be attributed to the injection of energy and momentum by stars that prevents free-fall collapse of molecular clouds. The dominant mechanism of this stellar feedback is debated theoretically: possible sources of pressure include the classical warm HII gas, the hot gas shock-heated by supernovae and stellar winds, the direct radiation from stars, and the dust-processed radiation field trapped inside the HII shell. In this talk, I will discuss how one can measure the pressures associated with these feedback processes using multiwavelength imaging (radio, infrared, optical, and X-ray), and I will present the results from applying these techniques to the giant HII region 30 Doradus, the largest star-forming region in the Local Group. For that source, I find that radiation pressure dominates close to the central star cluster, and I will consider the implications regarding the dynamics of 30 Dor and the regulation of star formation in the region.