Experiment dropped 17,000 wallets in 355 cities across 40 countries. Wallets with money returned at higher rates than those without in virtually all countries. Result contradicts rational self-interest predictions from economics. Neither economists nor nonexperts predicted higher returns for money-filled wallets. High civic honesty observed across nations. Additional data show altruism and aversion to self-perception as thief drive findings, increasing with dishonesty benefits. Wallet return rates correlate with country-level dishonesty measures like corruption indices and cheating experiments.