ArXiv is an online archive that stores hundreds of thousands of scientific papers in physics, mathematics, and other fields. The citations in those papers link to one another, forming a web, but you're not going to see those connections just by sifting through the archive.
So physicist Damien George and Ph.D student Rob Knegjens took it on themselves to create Paperscape, an interactive infographic that beautifully and intuitively charts the papers.
The infographic is a mass of circles. Each circle represents a paper, and the bigger a circle is, the more highly cited it is. The papers are color-coded by discipline--pink for astrophysics, yellow for math, etc.--and papers that share many of the same citations are placed closer together.
Via Lauren Moss, Dr. Stefan Gruenwald