Paraguay has one of the rare geological oddities. Only found in few other places (South Africa and Canada), Cerro Koi is the only location in South America where sandstone can be found in naturally occurring polygonal shafts.
The cost is free, however there are a few favelas nearby so it has been recommended by a few locals to go with a security escort unless you are in a large group. Otherwise if the locals hear you, they may come up the hill and take advantage of situation.
To this end, it was quite easy to ask the police to come with us. There is a police station very close to the Church (Nuestra Senora de la Candelaria) which is accustomed to these requests. Simply stop by, ask for them to come with you and be prepared to give them a tip at the end of the visit. The tip would be about 5000 PYG or more depending on their interaction.
The stones from Cerro Koi had been used for years, mostly as paving stones for the roads. While driving on the residential and smaller roads in Paraguay, you'll quickly know which came from Cerro Koi. The smaller stones make a smoother road, however now that the mountain is protected, they no longer pave with these stones.
Beaches are not a commonality in Paraguay. While there are many rivers in the country, very few are safe or clean for swimming. There is a man-made beach in Encarnacion, but that is a far drive for most.
Lago Ypacarai offers a partial solution. From a distance, the blue waters look inviting and refreshing on the hot days. However, the closer you get, the more you may realize that you don't want to go swimming. There is a lot of bacteria and various things in the water that do not make it a wise idea to actually swim here either.
But the park with the name of "Playa de Aregua" offers nice views of the lake, some barbeque and picnic spots, as well as some walking paths.
The park is patrolled, but I do not know the hours. Entry costs ~5000 PYG per car.
If you read my Asuncion page or possibly some other literature on Paraguay, you may know that Paraguay had the first railroad in South America.
Although there is work on going to restore some portions of these lines, most of it is run down and dilapidated.
Aregua has one of the original stations. The building is still in decent condition, but most the tracks have been removed except for a few places. There are a few old rail cars in the open air. It is free and worth a few minutes to walk around if you are a train enthusiast.
Today, the station is home to Estation-A (www.estacion-a.org.py) a cultural and civil project for developing the arts among other things.
Don Pablo's is a laid back restaurant in a quiet corner of a quiet town. There are a couple tables inside, however most of the tables are out on an extensive patio with a canopy of umbrellas and growing vines.
The service is okay, but not exceptional. Thankfully though, you are not paying for the service since the food here is quite inexpensive.
Favorite Dish: There are a number of pasta dishes, pizzas, sandwiches, salads, etc. The food we sampled was all good. Also my friends who brought me here said that the food is regularly of good quality.
Inside the same building is a small bakery and with some simple sweet treats. There are several types of fresh breads and a few sweet pastries.
The best way to see Aregua and at least five other little towns in the environs of Asuncion is by minivan with a guide. The whole trip with an "almuerza" thrown in and lots of cultural insights for the intrepid travellers would cost USD25 per person. I found this a very good investment, considering the fact that before doing so I was ready to leave Paraguay with very gloomy impressions.