Humans have explored the solar system for decades with various kinds of spacecraft. Some were designed to orbit the Earth and its neighbors, while others were made to study the outermost planets and their unique systems.
Most of the spacecraft we've sent into space have stayed within our general neighborhood, but just a select few of them are hurtling out of the solar system, headed for a long trip through interstellar space.
Venera 7 became the first spacecraft to land on another planet when it dropped onto the Venusian surface. Shortly after, Mariner 9 became the first probe to orbit Mars. Galileo would then become the first spacecraft to orbit Jupiter.
Several launches later, some of the most famous spacecraft still in action today are the Cassini probe at Saturn (which is close to ending soon), the New Horizons probe at Pluto (which now targets a Kuiper Belt Object), and the Juno probe at Jupiter.
Of all the spacecraft we've ever launched, Voyager 1 is the furthest away from us today. It was one of two satellites launched to explore the outer solar system, but because it gets energy from nuclear power instead of solar, it will stay functional even as it moves into interstellar space.