Athens

Athens is Greek alphabet-to-fluency in the tightest learning loop in Europe. The 24-letter alphabet takes a single weekend to read; the 30% of vocabulary that sits directly on Ancient Greek roots gives educated English speakers an unusual head start (democracy, philosophy, dialogue — these are still the same words); and the locals will not, for the most part, give you the English bail-out the way Stockholm or Berlin does.

Modern Greek is one syllable's worth of pitch-stress away from Ancient Greek for vocabulary, but the grammar runs at a healthy four-on-the-difficulty-scale: three genders, four cases, perfective/imperfective verb pairs that look Slavic but aren't. The Athenian café scene (frappé invented here in 1957, freddo cappuccino spreading through the rest of Europe in the last decade) gives you four-hour study sessions at €3 a coffee. Free Acropolis-area student tickets, university libraries, and an Exarchia bookshop scene mean Greek input is genuinely abundant.

The shape of Athens for a learner: Plaka and Monastiraki for the postcard tourist English, Koukaki and Pangrati and Exarchia for actual daily Greek. The metro empties at midnight and starts again at 5:30am, so a learner's evening calendar runs late — taverns till 1am, bouzoukia till 4am — and your spoken Greek will accelerate on the back of late-night conversations more than morning classes.