Today, concrete is the most widely used construction material worldwide. Strong, versatile, durable, and vector of economic development, this exceptional material is also the principal cause of greenhouse-gas emissions, material depletion and waste generation by the construction industry. Hence, reusing concrete elements extracted from obsolete building structures has large potential to significantly reduce the environmental impact of construction. To demonstrate the potential of such an unusual strategy for bridge construction, this paper shows the construction of the Re:Crete arch prototype. It is made of 25 reclaimed concrete blocks connected through post-tensioning to create a 10-m span arch. The complete design-and-build workflow of the prototype is presented, including the structural design of the arch, the sourcing of the reusable concrete elements and the assembly. The Re:Crete arch prototype mechanical properties and environmental impact are assessed through non-destructive investigation, load testing and Life-Cycle Assessment. The results show that the reuse of concrete blocks leads to a comparable structural behaviour as a similar arch made of new or recycled concrete, with an environmental footprint reduced by more than 70%.