ATLAS-3000, the backbone of CALA’s high-intensity laser infrastructure, is a 2.5 PW, 1 Hz Ti:Sa ultrafast laser. It comprises the MPQ’s former ATLAS laser as a frontend, which has been developed by our group over the past 2.5 decades into a 300TW laser system andcomplements it with a commercial 90-J amplifier from Thales LAS and a home-built final compressor. The final compressed energy of 70 J and a pulse duration of 27 fs makes it one of the leading Ti:Sa laser systems world-wide, and the world’s highest average-power PW laser system. Its pulses are intended to drive a variety of applications from the acceleration of ions for radiobiology and radiation oncology studies, over ultralow-emittance electronbeams as drivers for medically relevant high-brilliance x-ray sources all the way to studies of nuclear processes and high-field QED experiments. However, in order to drive all these applications on an internationally competitive level, not only raw power is key, but also the pulse-to-pulse stability, beam quality and spatiotemporal contrast of the system have to satisfy extreme demands.