To reach the end of the world, you could just hop on a bus. Number 403 must be one of Europe's most stunning journeys, starting in the prosaic surroundings of Cascais bus station but soon shaking off the townscape and climbing up to the Serra de Sintra and into the Parque Natural Sintra-Cascais. Into this wilderness is crammed an improbable amount of scenery: valleys speckled with farmhouses and cottages, blankets of pines climbing steep hills, the horizon a jagged perforation against a perfect sky.
The bicycle ride to the ultimate conclusion is even more rewarding. West from Cascais, you can pedal at a gentle, sea-level pace for 11km on a dedicated cycle lane. The sights along the way include the Boca do Inferno (well, you might as well combine the end of the world with the mouth of hell), then a series of superb beaches. A lighthouse stands guard at Cabo Raso, the point where the coast - and you - swerve sharply north. The wild isolation of this cape could convince you that you had reached the far end of Europe, but the Romans knew better: they correctly observed that the westernmost extreme of the continental mainland was the next headland north.
Before you start the long climb towards Cabo da Roca, pause at Guincho - a superb, west-facing beach that gets some of the best winds and waves in Portugal; Aerial Wind & Surf (00 351 214 674 327; www.aerial-pt.com) is one of several companies to offer equipment rental to take advantage of the elements, or you could just relax and watch the acrobatics of the expert kite-surfers.
Soon, the road gives up its unequal struggle to keep pace with a increasingly ambitious coastline, and turns inland; you will work up an appetite, and a thirst, as you climb steadily through the forest. From the signposted turn-off for Cabo da Roca, you expend almost all the potential energy that you have acquired as you accelerate through the village of Azoia; should you decide to stay here, there are rural tourism possibilities. The rocky road to the rocky cape unwinds extravagantly from here towards a cluster of maritime installations, presided over by a lighthouse. Brakes willing, you stop 140m above the sea itself, on the edge of a towering cliff.
A needle pays tribute to this being the "Ponto Mais Ocidental do Continente Europeu", but the view says it all: landmass collides with ocean in spectacular fashion. As a day trip, the end of the world is nigh-impossible to beat.