Astana's main draws cluster along the central axis of the left bank — a deliberate sequence of monumental architecture built since 1997 to make a capital city out of a Soviet provincial outpost. The walk from Khan Shatyr through the Bayterek Tower and on to the Aqorda and Palace of Peace and Reconciliation is the standard introduction — about three kilometres of glass, golden domes, and Norman Foster geometries.
Beyond the showpieces, the Hazret Sultan Mosque, National Museum, and Astana Opera are worth a half-day each. The right bank, with the older Nur-Astana Mosque and the Central Park, gives a sense of what the city was before the rebuild.
The neighbourhoods to wander are the Left Bank (monumental, planned, slightly unreal), the Right Bank (Soviet-era, more lived-in), and the Expo District around the Nur Alem sphere left over from Expo 2017. The contrast between them is the most interesting thing about Astana as a city.