The locations of cities, environmental changes, ever-increasing heights of tall buildings, and focus on high-performance design will create challenges for tall building design in the 21st century. This dialogue will discuss microclimates of tall buildings. In particular, it will focus upon the impact 21st century climate and changing air contaminants have on tall buildings. Tall buildings should be designed to be resilient; researching and exploring related microclimate topics can inform our design. Topics include: the integration of tall buildings within the city to achieve optimal energy performances; the latest stack effect data, monitoring, and control; elevator door opening sequences and their impact on elevator shaft pressure; the integration of natural ventilation in tall buildings; how energy consumption changes with height; and cloud computing and advanced modeling techniques on tall building design.