Esplanadi, a wide, tree-lined boulevard across a mishmash of tramlines from the harbour, is Helsinki at its most charming. A couple of blocks north of its eastern end, the suavely refurbished City Museum at Aleksanterinkatu 16 (Mon–Fri 11am–7pm, Sat & Sun 11am–5pm; free) offers a microcosm of 450 years of Helsinki life through wonderful interactive exhibitions.
Just west of City Museum is Senate Square (Senattintori), dominated by the exquisite form of the Tuomiokirkko (Cathedral; June–Aug daily 9am–midnight; Sept–May Mon–Sat 9am–6pm, Sun noon–6pm). After the elegance of the exterior, the spartan Lutheran interior comes as a disappointment; more impressive is the gloomily atmospheric crypt (entrance on Kirkkokatu; June–Aug daily 9am–midnight; Sept–May Mon–Sat 9am–6pm, Sun noon–6pm), now often used for exhibitions. West across Unioninkatu, the city’s most spectacular interior decoration awaits in the soaring ceilings and mesmerizing decorative painting of the National Library of Finland (Mon–Fri 9am–6pm, plus some Sat; free).