#include<bits/stdc++.h>
using namespace std;
#define int long long
#define PII pair<int,int>
#define lson 2*p
#define rson 2*p+1
#define x first
#define y second
const int N=5e5+10;
const int mod=1e9+7;
int a[N];
int d[65];
void insert(int x) {
    for(int i=60;i>=0;i--) {
        if(x>>i&1) {
            if(d[i]) x^=d[i];
            else {
                d[i]=x;
                return ;
            }
        }
    }
}
int query() {
    int ans=0;
    for(int i=60;i>=0;i--) {
        if((ans^d[i])>ans) ans^=d[i];
    }
    return ans;
}
void solve() {
    int n;
    cin>>n;
    memset(d,0,sizeof d);
    for(int i=1;i<=n;i++) {
        int x;
        cin>>x;
        insert(x);
    }
    cout<<query()<<endl;
}
signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int T=1;
	cin>>T;
	while(T--) {
		solve();
	}
}