In Bangkok's Chinatown, it pays to climb the stairs. TAX, a speakeasy above street level, builds its cocktails on vinegars, tea infusions and house ferments, while Wallflowers Upstairs rises from florist and café to a rooftop bar pouring garden-inspired drinks. In Thonglor, Tichuca Rooftop Bar spreads its jungle theme over several levels, around a glowing tree sculpture.