This image of water droplets stabilized with gold nanoparticles was taken using optical microscopy. The nanoparticle ligands - organic molecules used to stabilize the small gold particles - direct the behavior of these nanoparticles. By changing the nanoparticle ligands, the particles assemble at and stabilize the oil-water interface, resulting in stable emulsions comparable to every-day emulsions such as milk or salad dressing. Addition of a hydrogel, such as gelatin, can further stabilize the assemblies, sometimes resulting in the bubbles seen within these droplets.