Teams of racers test themselves by hurtling down challenging, obstacle-filled courses in homemade, motorless soapbox race cars.

Teams battle against the clock in an extreme downhill race at the landscaped gardens of Villa Borghese in Rome.

More thrills, spills, customer carts and crashes in this extreme downhill battle at the Eduardo VII Park in Lisbon.

The normally tranquil streets of East Melbourne transform into a festival of gravity racing; 56 teams take on a ferocious course littered with obstacles.

Teams of racers test themselves by hurtling down challenging, obstacle-filled courses in homemade, motorless soapbox race cars.