Overview of the sympathetic eruptions of two filaments on 2015 November 15-16. (a1)–(a3): Sequence of GONG Hα images displaying evolutions of the two filaments (F1 and F2). The red and blue contours in panels (a1)–(a2) outline the filament fragments of F1 and F2, respectively. Ribbons produced by eruptive F1 and F2 and remanent F2 are denoted by arrows in panels (a2)–(a3). The GOES SXR 1–8 Å flux variation overlaid in panel (a3) reveals two B-class flares caused by eruptions of the two filaments. (b1)–(b3): Corresponding composite images of SDO/AIA 131 Å, 304 Å, and 171 Å channels. (c): Corresponding SDO/HMI LOS magnetogram. (d1)–(d2): Difference images from SOHO/LASCO C2 showing two successive CMEs driven by the sympathetic eruptions of F1 and F2. An animation of Hα, AIA composite, and LASCO C2 images, covering 21:30 UT on November 15 to 03:54 UT on November 16, is available online.