Looking up at the starry sky, we can imagine the proverbial infinite vastness of space. However, the true distances to the stars are not revealed to us. In astronomy, determining distances is indeed difficult. Only in 1838 did F. W. Bessel succeeded in making the first reliable measurement of a star´s distance. And only a hundred years ago the size of the Milky Way was unknown. Only the pioneering work of astronomer H. Swan Leavitt opened the door to the distances to the nearest galaxies. The lecture presents some of the methods used in astronomy today. Some measure the distances to objects in the solar system and to the nearest stars, while others extend to the most distant galaxies. But they only work for a limited range at a time, and so they complement each other to form what is known as a distance ladder.