Winter intersession and summer courses are also offered, but not required. In the spring all students choice an intersession. Each year the spring intersession options change and financial aid is offered. The wind tower was installed during the winter 2015-2016 intersession. However, Serbia and Russia rejected it outright, and continued United Nations intersession was fruitless. The school also adopted a new academic calendar to include intersession. Students have many options to pursue during intersession. This differs from many colleges at which January Term or "Intersession" is optional. Most years, Upper School students are taken on non-traditional learning experiences during "Intersession". This period is called "Expeditions," it was formerly called "Intersession". Alumni often teach Intersession courses and lead overseas trips along with faculty members. The three days before April Break (Spring Break) are known as Intersession. At Washington & Jefferson College, Intersession is a three-week term in January. Intersession is a short break or mini-term between the traditional, standard academic terms.