The COBE Differential Microwave Radiometer (DMR) instrument has observed that the full microwave sky is remarkably uniform in the millimeter to centimeter wavelength range. However at a small level (<=10-5), there is large-scale structure. The natural interpretation of this structure is as the imprint of spatial curvature fluctuations, primarily due to density variations, in the early universe. The results are supportive of gravitational instability theories of structure formation and inflation/quantum cosmology models. The natural energy scale for inflation then is ~1016 GeV. A failure to find fluctuations within a factor of two of the COBE DMR level would have contradicted gravitational instability models with a near scale-invariant spectra.