Volume 1 of the FCC Feasibility Report presents an overview of the physicscase, experimental programme, and detector concepts for the Future CircularCollider (FCC). This volume outlines how FCC would address some of the mostprofound open questions in particle physics, from precision studies of theHiggs and EW bosons and of the top quark, to the exploration of physics beyondthe Standard Model. The report reviews the experimental opportunities offeredby the staged implementation of FCC, beginning with an electron-positroncollider (FCC-ee), operating at several centre-of-mass energies, followed by ahadron collider (FCC-hh). Benchmark examples are given of the expected physicsperformance, in terms of precision and sensitivity to new phenomena, of eachcollider stage. Detector requirements and conceptual designs for FCC-eeexperiments are discussed, as are the specific demands that the physicsprogramme imposes on the accelerator in the domains of the calibration of thecollision energy, and the interface region between the accelerator and thedetector. The report also highlights advances in detector, software andcomputing technologies, as well as the theoretical tools /reconstructiontechniques that will enable the precision measurements and discovery potentialof the FCC experimental programme. This volume reflects the outcome of a globalcollaborative effort involving hundreds of scientists and institutions, aidedby a dedicated community-building coordination, and provides a targetedassessment of the scientific opportunities and experimental foundations of theFCC programme.