The telomere replication landscape. From left to right is diagrammed on the telomere a replication fork, a G-quadraplex (G4) and a t-loop. A number of proteins relevant to the review are cartooned as well. These include CtIP, NEIL3, ATRX, BLM, BUB1:3, RTEL, PIF1, EXO1, TRF1 and TRF2. In addition, the presence of ROS, the formation of TERRA and the complete Shelterin complex are shown as well. Because of these proteins, unusual structures, modifications and various processes a telomere is a priori difficult to replicate through. Resolution of these replication roadblocks and efficient fork restart are pivotal for telomere integrity.