Singleton: how can destructor be called twice?

I asked a question about singleton implementation a few minutes ago, I've got very good answer from @LightnessRacesinOrbit.

But I cannot understand why in the next example if I instantiate Singleton in variable inst its destructor called twice?

#include <iostream>

class Singleton
{
public:
    ~Singleton()  { std::cout << "destruction!\n"; }

    static Singleton& getInstance() 
    {
        static Singleton instance;
        return instance;
    }

    void foo() { std::cout << "foo!\n"; }

private:
    Singleton() { std::cout << "construction!\n"; }
};

int main()
{
    Singleton inst = Singleton::getInstance();
    inst.foo();
}

Output:

construction!
foo!
destruction!
destruction!

Live demo

To be more correct, I understand why it is called twice. But I cannot understand how it can be called twice if after first destructor the instance of the class was destroyed? Why there is no exception?

Or it was not destroyed? Why?