Quantum computers are expected to do everything from complex modeling to code-breaking. But they are still a long way off. On the other hand quantum simulators are finally here. Unlike quantum computers, they have to be tailored specifically for the problem at hand. Quantum systems are extremely fragile: almost any interaction with the outside world will destroy the delicate correlations. It has taken 30 years to develop the technology required to keep the particles isolated enough to finish the simulation unimpeded, yet interactive enough to let physicists extract the answer. The current record is 350 qubits using trapped ultracold beryllium ions arranged in a crystalline pattern, capable of carrying out the unusual mathematical calculations made possible by the quantum world.