Chlumecký rybník is a large, 32-hectare pond that's a popular local spot for a dip, especially during the summer. It's a former mine and one of the few remaining ponds from a huge system built back in the 15th and 16th centuries.
The main draw is the sandy beach, which is great for kids and families. The water is usually clean throughout the summer, making it a nice place for a swim. Away from the main beach, you can even bring your dog for a splash. There's also a small stand where you can grab a beer or a snack.
While the main beach is sandy, access to the water around the rest of the pond can be tricky, with muddy spots and sharp stones, so watch your step. It's a natural spot, so don't expect a lot of facilities. It's also a fishing area, so be mindful of people fishing.
The main sandy beach can get really crowded on hot summer days.