The Palena is one of Patagonia's great bi-national rivers, rising in Argentina and crossing the cordillera into Chile through country so remote that much of it is still reached by boat or plane rather than road. Glacial and volcanic influence gives it the milky-green colour typical of the region, with real volume even outside flood, and brown and rainbow trout hold in a river with genuinely limited angling pressure. Streamers and sculpin patterns fished deep account for the biggest fish, with dry-dropper tactics working the softer margins in low water. This is expedition water in the true sense — float trips, camps, and days where the nearest road might be an hour's flight away — and it rewards the effort accordingly.

• Volcanic glacial