Genomic data and annotations are rapidly accumulating in databases such as the 
UCSC Genome Browser, NCBI, and Ensembl. Given the massive scale of these genomic 
databases, it is important to be able to easily retrieve known data and 
annotations of a specified genomic locus. For example, for a newly identified 
cis-regulatory element bound by a transcription factor, questions that 
immediately come to mind include whether the element is near a transcriptional 
start site and, if so, the name of the corresponding gene, and whether the 
histones or DNA at the locus are modified. The UCSC Genome Browser organizes 
data and annotations (called tracks) around the reference sequences or draft 
assemblies of many eukaryotic genomes and presents them using a powerful 
web-based graphical interface. This protocol describes how to use the UCSC 
Genome Browser to visualize selected tracks at specified genomic regions, 
download the data and annotations for further analysis, and retrieve multiple 
sequence alignments and their conservation scores.