If you are in Tandil and want some time away from the bustle of the city, head out for the hilltop park Complejo Cerro el Centinela. Located 6 km out of town, this is a great place to do a little hiking and then just sit back, relax, and bask in the sun once you are up there, quietly taking in the fresh countryside air and the beautiful surroundings with its little sierras (hills). You'll find a huge Asado for lunch and a restaurant with outdoor tables that will remind you of the good, old-time taverns. There's a bakery as well where you can enjoy some yummy afternoon snacks. Overall, an ideal place to visit on a quiet holiday afternoon.
Also, if you're not too keen on hiking, you may use the Chairlift (AR $130 per person) or rent a mountain bike (AR $180 per hour). Or you may simply take a taxi from the city that will take you right up at the park.Places nearby:
Piedra Movediza: Tandil's Moving Rock 5 km / 3 mi
Playa Grande: Perhaps Argentina's Best Beach 161 km / 100 mi
Playa Varese: A Relaxing Paradise in Mar Del Plata 162 km / 100 mi
Museo de la Plata: Preserving the Natural History of Argentina 293 km / 182 mi
Plaza de Mayo: Buenos Aires Plaza of Hope and Independence 313 km / 195 mi