Túnel da Caldeira from Caldeira da Graciosa

At just 0.9km, Túnel da Caldeira from Caldeira da Graciosa is short but deceptively intense — 53m of elevation packed into a brief, breathless effort. The average gradient of 5.9% disguises ramps of 13.4% — the kind of gradient that turns plans into prayers. It's over before the legs know what happened — a short, explosive effort where momentum is everything. Located in Azores, Portugal.