For a locally compact topological group G there exists a non-trivial measure μ on the Borel sets such that
μ is invariant meaning μ(gS) = μ(S) for a Borel set S and g ∈ G.
μ is countably additive meaning for disjoint Sk.
μ(S) is finite for any compact Borel set S.
μ is unique up to a multiplication by a positive scalar.