West of Raxrujá a recently paved highway crosses steamy, thinly populated lowlands – the flatness of the landscape broken periodically by soaring forest-topped karst outcrops – to the magical Parque Nacional Laguna Lachúa, a near-circular lake surrounded by a dense tropical jungle. One of the least-visited national parks in Central America, this is a supremely beautiful, tranquil spot, with pristine azure-blue waters perfect for swimming. About 2km in diameter and over 200m deep, Lachúa is thought to be a natural sinkhole in the limestone crust, though its circular shape has led to speculation that it could have been formed by a meteorite impact. The rangers are extremely protective of this magnificent national park, and visitors have to carry back all non-biodegradable material.
The reserve is home to tapir and all the main Central American wild cats, including jaguar, but though these creatures usually prove elusive, you’re virtually guaranteed to hear howler monkeys, and armadillos and otters are often seen. There’s also an abundance of exotic birdlife (around three hundred species have been recorded here), including snail kites and flycatchers, but watch out for mosquitoes.