What are other attractions than Oslofjord that are worth visiting in Oslo?

The other must-see attractions in Oslo are:<a href='/nationaltheatret-norway-l165966/'>Nationaltheatret, Norway</a><a href='/akershus-fortress-l4243/'>Akershus Fortress</a><a href='/royal-palace-oslo-l4245/'>Royal Palace, Oslo</a><a href='/oslo-opera-house-l4237/'>Oslo Opera House</a><a href='/oslo-city-hall-l123080/'>Oslo City Hall</a>

What are the most popular Oslofjord tours and tickets?

The best Oslofjord tours and tickets are:<a href='/oslo-l38/oslo-fjord-2-hour-sightseeing-cruise-t576/'>Oslo Fjord 2-Hour Sightseeing Cruise</a><a href='/oslo-l38/oslo-fjords-3-hour-evening-buffet-cruise-t40266/'>Oslo Fjords 3-Hour Evening Buffet Cruise</a><a href='/oslo-l38/oslo-highlights-3-hour-bike-tour-t25950/'>Oslo Highlights 3-Hour Bike Tour</a><a href='/oslo-l38/oslo-grand-city-tour-and-fjord-cruise-t74686/'>Oslo: Grand City Tour and Fjord Cruise</a><a href='/oslo-l38/oslo-oslofjord-2-hoursightseeing-cruise-with-lunch-t389343/'>Oslo: Oslofjord 2-HourSightseeing Cruise with Lunch</a>