The cosmic distance ladder is a sequence of observational methods used in astronomy to estimate the distances to increasingly distant astronomical objects. These methods are tiered, starting with techniques based on stellar parallax to measure local distances within the same galaxy. Successive rungs involve using standard candles, which are types of celestial objects that exhibit a known intrinsic luminosity, allowing astronomers to calculate distances based on how brightly they appear from Earth. The use of these distance indicators allows measurements to extend outward, linking local galactic structures to features within neighboring galaxies and ultimately providing constraints on the expansion rate of the universe. The accurate calibration of each step is crucial, as the precision of the furthest measurements depends on the accuracy of the measurements taken at the closest steps.