What pilgrims actually do at Kurukshetra is bathe. The plain carries a large number of tanks and ponds, each attached to an episode of the epic or to a figure in it, and the practice is to bathe at them in sequence and to offer rites for ancestors. The most concentrated occasion is a solar eclipse, when bathing at Kurukshetra is held to carry exceptional merit and the tanks draw very large crowds from across northern India.
Diana Eck has described how Indian sacred geography works by exactly this kind of duplication and linkage, in which a landscape is mapped by story and then made usable by a circuit of bathing places, so that a pilgrim moves through a narrative on foot. Kurukshetra is a clear case: the war is not commemorated by a monument to the war but by a network of water.
Whether a historical battle underlies the Mahabharata is a separate question and a genuinely open one. Archaeological work in the region has recovered occupation of the relevant periods without producing anything that identifies a specific conflict, and scholarly opinion ranges from a real dynastic war much smaller than the epic to no single event at all. The atlas holds the identification as traditional, which is how the pilgrimage itself treats it.