The most spectacular places on the planet that have the most to lose as humans reshape the world

As humanity transforms the world, we're putting many of our most spectacular natural environments at risk.

Threats to many of the world's natural wonders are growing, according to a 2017 report by the International Union for Conservation of Nature (IUCN), which evaluates the threats faced by natural UNESCO World Heritage Sites. These sites include many of the most iconic wild places on the planet, including the Great Barrier Reef and snow-topped Kilimanjaro.

Beyond being beautiful, these are important places both for nature and humanity. As the report's authors wrote, "[t]hey harbour unique ecosystems and species, support livelihoods, contribute to climate stability and buffer against natural hazards."

Yet for more than a third of these sites, the outlook is critical or of significant concern. In places like Florida's Everglades where the threat level is critical, immediate large-scale action is needed for preservation. For sites like the Galápagos that have an outlook of significant concern, significant measures need to be taken to stave off deterioration.

The biggest pressures on these critical sites — and on the rest of the natural world — include invasive species, climate change, tourism, human activities like hunting and fishing, and development. Looking to the future, climate change and severe weather are expected to become even more significant causes of harm, as will road construction and oil and gas development.

These are far from the only crucial natural sites that are threatened by human activity. But they are some of the best-known, and it's worth remembering that if we can't protect these, we don't have much chance of protecting the rest of the world.

Here are some of these spectacular places we could lose if we don't take action as soon as possible.

SEE ALSO: The Great Barrier Reef is one of the most spectacular places on the planet — here's what it looks like as it dies off

Monarch Butterfly Biosphere Reserve, Mexico

IUCN Status: Critical

Illegal logging, extreme weather, and climate change-related disruption to seasonal migrations are all causing severe threats for this site, where Monarch butterflies make the longest-known insect migration to spend the winter.

Iguaçu National Park, Brazil (and Iguazu National Park, Argentina)

IUCN Status: Threatened

There are a number of threats to these falls at the border of Brazil and Argentina, including invasive species, hunting, logging, water pollution, dams, and climate change.

Tropical Rainforest Heritage of Sumatra, Indonesia

IUCN Status: Critical

Development and deforestation, especially by palm oil harvesters, has put the rainforests of Sumatra in critical condition.