$d$ = 2.5$\pm$0.5 kpc for the  complex.

With the aim of investigating the interplay between the massive stars belonging to Pis24 and the different components of the neighbouring interstellar material, we analyzed ,  and  images obtained at CTIO, VLA radio continuum observations at 1.465 GHz, and CO(1-0) observations obtained using the NANTEN telescope, as well as IRAS archive images (IRAS-HIRES) at 60 and 100 $\mu$m, and GLIMPSE IRAC archive images in the near- and mid-IR. Optical line ratios are extremely useful in investigating the excitation conditions in different areas of the complex. High resolution radio images lead to the distribution of ionized gas in highly obscured regions, and in the derivation of the physical parameters of ionized regions. Images in the mid and far infrared lead to characterization of the interstellar dust in the complex. As a substantial amount of molecular gas is expected to be present in star forming regions, we also observed the whole complex in the CO(1-0) line at 115 GHz.

This is the first of a series of papers dealing with this complex. This paper focusses on some of the most interesting structures in the complex, excited by the massive stars in the open cluster Pis24. 