The Tagus estuary has carried commerce, conquest, and caravels for eight centuries, but the river's modern role as Lisbon's liquid promenade began in earnest after Expo '98 transformed the eastern waterfront. Today the Tagus serves as both mirror and stage, reflecting the terracotta grid of Alfama and the Manueline filigree of the Torre de Belém while offering a vantage no cobbled miradouro can match. A Lisbon boat tour with drinks transforms that geography into theater, the city's seven hills rising in amphitheater tiers as you glide past the rust-red span of the 25 de Abril Bridge and the outstretched arms of the Cristo Rei monument across the south bank. The river itself is a brackish hybrid, tidal and temperamental, its width swelling to more than ten kilometers at the Mar da Palha before narrowing again near Belém. That breadth means the Tagus catches light differently than the Seine or the Arno—at sunset the water turns molten, a sheet of hammered copper that doubles every facade and monument in shimmering duplicate. Most operators depart from the Doca do Bom Sucesso near Belém or the Estação Fluvial in Cais do Sodré, threading west past the Padrão dos Descobrimentos and the MAAT's undulating white roof before pivoting toward open water. The drink itself—whether a chilled vinho verde, a gin-tonic with Sikkim or Sharish, or an open-bar pour on a sunset party cruise—is less accessory than anchor, a reason to linger on deck while the skipper narrows the throttle and lets the cityscape scroll past at walking speed. Tagus river cruises with drinks range from intimate catamarans with welcome cocktails to floating dance parties with live DJs and open bars, but all share the same essential choreography: boarding near golden hour, a slow westward arc past the Monument to the Discoveries and the fortress of São Julião da Barra, then a pivot east as the sun drops behind the Sintra hills and the city lights begin their staggered ascent. The swim-stop itineraries add a plunge into the brackish current off Cacilhas, where the water is cool even in August and the skyline of Baixa shimmers in the middle distance. The experience is less about narration than atmosphere—the slap of water against fiberglass, the clink of ice in a plastic cup, the way the Ponte 25 de Abril turns from red to silhouette in the span of fifteen minutes.