Places where people sit at the bar, as opposed to tables, are the best for this, especially if they are in places frequented by solo (e.g. business) travelers.

Places where people sit at the bar, as opposed to tables, are the best for this, especially if they are in places frequented by solo (e.g. business) travelers. Bars in hotels, airports and train stations (or onboard trains!) are often the most social places around. I've had many good conversations with Germans at hotel bars in various parts of Germany :)