What lake, shared with two neighbours, is one of the oldest in Europe at over a million years and sits at a triple border?

• A Lake Ohrid
• B Lake Prespa ✓
• C Lake Trichonida
• D Lake Kerkini

Lake Prespa, divided between Greece, Albania, and North Macedonia, is one of Europe's most ancient lakes at over one million years old and hosts unique endemic species including the Prespa trout.