Directions for all Holiday Inn guests:
From MHG (airport) to HI City:
Take tram no. 6 to Strohmarkt, then walk towards the water tower (you can see it on one end of the road) on Planken (that's the street where the tram stops). At the second street on your right side, turn right (it's a small street between "Engelhorn" and "Engelhorn Trendhouse". After 150m you can see the HI (it's left of "Engelhorn Sports").
From Mannheim main railway station:
Take tram no. 3 or 7 to Strohmarkt. Then walk the same way as above.
By car:
Use your GPS

, the adress is N6 house number 1.