Hahn–Mazurkiewicz Theorem: Suppose $X$ is a nonempty Hausdorff topological space. Then the following are equivalent: 1. there is a surjection $[0,1]\to X$, 2. $X$ is compact, connected, locally connected and second-countable. It follows that a Hausdorff space satisfying the conditions of (2) is a quotient of $I = [0,1]$. Cor: Every connected compact manifold is a quotient of $I$. Since $I$ is a quotient of $\mathbb{R}^n$, we have your answer. Cor: Every compact $m$-manifold is a quotient of $\mathbb{R}^n$ for any $n\geq 1$.