Spring has arrived in the Netherlands, and with it the riotous colors of fresh-bloomed bulbs, which canvas its flat landscape in every direction. April is peak tulip season, depicted by generations of painters from Claude Monet to Jan van Goyen, and there’s no better way to see them then on a road trip through the countryside. A highlight: Keukenhof, a garden in Lisse open from late March to mid-May and a sight to be seen with 70 acres of parkland blanketed in some 7 million flowers. For solo travelers, few destinations beat the Netherlands for safety, friendliness, and navigability. Try not to miss King’s Day, a national holiday in April honoring the monarchy, when everywhere from Amsterdam to the Hague celebrates with open flea markets, street performances, and everything oranj.