We locate approximately one hundred TRMM PR overflights of tropical cyclones whose eyewalls are entirely or mostly within the PR swath. We discuss different definitions of convective towers. We choose a definition that is easy to implement in an automated search and that locates those towers that are most often associated with tropical cyclone intensification. Next, we describe the vertical and horizontal structure of convective towers in cyclone eyewalls. We contrast the structure of towers within eyewalls with those outside of eyewalls. Last, we quantify how often cyclone intensification is associated with the presence in the eyewall of at least one PR pixel that is a convective tower. We find that intensifying cyclones are more than twice as likely to have a convective tower in their eyewall than non-intensifying cyclones. In particular, 50% of weak, intensifying cyclones (categories 1 or 2 on the Saffir/Simpson scale) have a convective tower, vs. 20% of weak, non-intensifying cyclones. Thirty-five percent of strong, intensifying cyclones have a tower, vs. 15% of strong, non-intensifying cyclones.