The 40th Summer Conference on Topology and its Applications will be held July 13-17, 2026, in Split, Croatia at the Faculty of Science of the University of Split. The goal of this project is to support the attendance of US-based researchers. Having completed four decades of annual meetings attracting scholars from across the globe, this conference series will continue its legacy of advancing the field of topology and its applications. Consequently, it is important to have as many US-based researchers attend as possible so that they may disseminate their work and stay current with the global research trends in topology. SUMTOPO was established in 1986 and attracts about 200 participants each year to discuss the latest advances in topology and its applications to other fields; it is one of the largest and longest-running conference series on topology and typically alternates meeting locations between the USA and Europe to sustain and promote an international community of researchers. The 40th annual meeting is expected to attract a broad spectrum of topologists to commemorate its 40th meeting, and the primary goal of this project is to support travel for early-career researchers, graduate students, and researchers from institutions throughout the country, including those with limited support for travel, as they would likely be unable to attend otherwise. For more details, visit https://events.pmfst.unist.hr/sumtopo/. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.