• Bring a jacket for Cisternerne, since the underground rooms stay between 4°C and 16°C, even on hot summer days
• Strollers stay up top: park them in or outside the entrance pyramid, as the stairs down rule out strollers and wheelchairs
• Toilets in the orange house about 200 m from Cisternerne, since there are none down in the cisterns

Søndermarken is a romantic landscape park from the 1700s, with winding paths, a lake, wide lawns and a preserved Norwegian log cabin. Its big draw sits underground: Cisternerne, the city's old water reservoir, now a dim, echoing art space with stalactites hanging from the ceiling. Kids walk down through a glass pyramid into three cold, cavernous rooms. Copenhagen Zoo's main entrance is just across Roskildevej.