North of Crawford Notch, the highway joins the Ammonoosuc River headwaters as they flow toward the Connecticut River, passing Bretton Woods and the access road for the Mount Washington Cog Railway (603/278-5404, spring-fall, adults $69). The giant Omni Mount Washington Resort (603/278-1000, $199 and up) dominates the surrounding plain, its Victorian luxury no longer standing in such grand isolation below the peaks of the Presidentials now that a ski resort sits across the highway and motels and condos squat around its skirts. Built at the turn of the 20th century by Pennsylvania Railroad tycoon Joseph Stickney, the Mount Washington Hotel received its most lasting recognition as host of the 1944 United Nations International Monetary Conference, the historic meeting of financiers from 44 nations that established the World Bank and chose the dollar as the global standard for international trade.

Climbing the mountains behind the hotel, the Mount Washington Cog Railway was built in 1869 and has a maximum grade of 37.5 percent, surpassed by only one other non-funicular railroad in the world, high up in the Swiss Alps. One cinder-spewing engine runs on coal, but others have been adapted to run on eco-friendly biodiesel. This historic “Railway to the Moon” takes over an hour to ratchet up the three-mile track to the often windy, cold summit. You can take a round trip, or you can ride up and hike (or ski) back down.

Much more active and exciting than the slow chug up the cog railroad is the Bretton Woods Canopy Tour ($89 and up), which takes you up into the top of the trees by way of cables, bridges, and zip-lines.