If you have but one place to visit, Rome.
Romans flirt like no other citizens anywhere else.
It's not necessarily more or less flirting than in other countries, but a specifically Roman style of flirting. Just be sure to keep watching when you catch an eye while walking. Or just have a beer at a sidewalk bar, and watch the Roman men and women and boys and girls. It may use the same coins, it may have the same central government, but is another world, another time, another place. The Republic of Venice was also, and at the same time, the very model of a police state, with boxes for denunciations like mailboxes, and a secret police apparatus that would give the Checka, the KGB, the Geheim Stats Polizei, a run for their moneys.