Abstract: It remains an open problem whether the 3D incompressible Euler equations can develop finite-time singularity from smooth initial data in the whole space. Recent numerical results indicate the potential existence of self-similar finite-time blowups with multi-scale features. Different from the conventional one-scale blowup that has been established for many models of the 3D Euler equations, this new type of blowup is closely related to traveling wave solutions and may provide a new approach to studying Euler singularity. We will first present some related numerical findings, and then we will show that multi-scale self-similar blowups can be proved analytically for a simple model of the 3D Euler equations.