What were the first strands of DNA observed through?

The first strands of DNA were observed through the use of X-ray crystallography, a technique that allows researchers to visualize the atomic structure of molecules. Notably, Rosalind Franklin's X-ray diffraction images in the early 1950s provided critical insights into the helical structure of DNA. This method revealed key details about the dimensions and shape of the DNA molecule, ultimately contributing to the understanding of its double helix form.