$\mathbb{R}$ is union of countable collection of disjoint open intervals

Any open subset of $\Bbb R$ is a at most countable union of disjoint open intervals. [Collecting Proofs]
But I have a question about how $$\mathbb{R}$$, which is open subset of $$\mathbb{R}$$, can be expressed as union of countable collection of disjoint open intervals. In my intuition, it seems not possible.... Thanks for your help.
Open intervals in $$\Bbb R$$ are allowed to extend to $$\infty$$, so $$(-\infty,\infty)$$ is one open interval that is all of $$\Bbb R$$.
• In one sense it is not an end point, because the interval is open. The use of $\infty$ means there is no end point. – Ross Millikan Dec 25 '19 at 14:49