The "tall thing" on a cruise ship is usually the Stack (or Funnel). While they traditionally served to vent smoke and exhaust from the massive engines, in 2026, modern funnels are high-tech structures that house Scrubbers—advanced filtration systems that remove sulfur and soot to meet environmental regulations. They are also used as iconic branding elements; for example, Carnival's "Whale Tail" or Disney's red funnels. Aside from the funnel, you may see a Mast at the very top, which holds the ship's radar equipment, navigation lights, and satellite communication "domes" (Radomes). On some ultra-modern ships, you might even see a "North Star" (a glass observation pod on a giant arm), but if it looks like a smokestack, it is the vital lungs of the vessel's propulsion system.