Observation of quantum mechanical effects in objects visible to the unaided eye has long been thought impossible due to the overwhelming effect of thermal excitations at room temperature. Recent proposals suggest that a nano- or micro-mechanical oscillator my exhibit quantum effects if optically cooled by viscous radiation pressure, despite the thermal agitation arising from its stiff mechanical attachment to the environment. Here we propose an optical trap that does not contribute thermal noise, unlike a stiff mechanical connection. We show how the radiation pressure from two laser beams can optically trap a free mass, and we demonstrate the technique experimentally with a 1 gram mirror. For the first time optical forces are seen to completely dominate the dynamics of a macroscopic object, allowing for larger reductions in temperature than was previously possible. The observed optical trap has a maximum eigenfrequency of 5 kHz and a Young's modulus of 1.2 TPa, 20% stiffer than diamond. This technique both generates extreme cooling, and mitigates the detrimental effect of thermal decoherence. The lowest effective temperature measured is 0.8 K, a factor of 370 below ambient room temperature, limited by technical noise in our apparatus. Temperature reductions 10 orders of magnitude below ambient are within reach through experimentally realizable parameters, which will enable the 1 gram mirror to approach the ground state. In contrast to previous work, we also show how the dynamical lifetime of the state, in the presence of thermal decoherence, may be extended by up to 7 orders of magnitude for this system. The proposed technique should expose the quantum-classical boundary in the strikingly large regime of gram-scale objects with 10^22 atoms.