In metazoans transcriptional enhancers and their more complex relatives, locus control regions, are often located at great linear distances from their target genes. In addition, these elements frequently activate different members of gene families in temporal sequence or in different tissues. These issues have complicated understanding the mechanisms underlying long-range gene activation. Advances in primarily technical approaches, such as chromosome conformation capture (3C) and its derivatives have now solidified the idea that distant regulatory elements achieve proximity with their target genes when they are activating them. Furthermore, these approaches are now allowing genome-wide views of chromosome interactions that are likely to include regulatory, structural, and organization aspects from which we will be able to understand more about nuclear structure. At the base of these advances are experimental approaches to localize protein-binding sites in chromatin, to assess remodeling of chromatin and to measure interaction frequency between distant sites. Examples of these approaches comprise this review