You can download a
pdf-map 
of Louvain-la-Neuve.
The building is named "le Cyclotron" or "Bâtiment Marc de Hemptinne" and is located at F8 on the map (building #1).
By car ...
From the E411 motorway, left 8a, take the third exit of the roundabout (thus left direction), then first on the right "Boulevard
Baudouin Ier", pass in front of the gaz station Q8, and use the P3 carpark (free) on the left with the roundabout. Attention
the P1 carpark is a private carpark which necessite a label UCL. For more infos on the carparks.
By train , walking directions...
The train station is located at D6/7 (label SNCB - building #18) on the downloadable map.
The building is 10 minutes walk from the train station.
When you get out of the train station you will arrive in the street “Rue des Wallons” that you should take to the left when the train station is in your back, which is also the direction where the street is going up. You climb up this street which zigzags a bit for 5 minutes. You will go across a first place named “place des Wallons”, then after more walk you will have to climb a few steps in a stair and after a last zigzag to the right through “Place Galilée” you will arrive at the “Place des Sciences” which is a big place with a wooden floor in the middle and a big concrete building with not many windows which is the “Bibliothèque des sciences” (Science Library, building #7 on the map). On your right there is an octogonal building named “Salmigondi” or "Pythagore" (about #28a on the map), just in front of the Bibliothèque des Sciences. You pass this octogonal building and just after you turn to the right. You will arrive on a parking lot. Then you take slightly to the left across the parking lot and (at least during the winter) you should see to the right a grey high chimney. You go towards this chimney which is along a path (“Chemin du cyclotron”; the chimney is the little blue square on the map). Just besides this chimney you will find a small pedestrian tunnel going under the motorway(“Boulevard Baudouin Premier”).
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